Nintendo, for the past couple of generations in which system memory has mattered, has done the bare minimum to cater to the issue. Sometimes it's gotten away with that, but it's been a stick with which the company's been beaten over the past few years. In the Wii and DSi era download games were only just starting to emerge and a lack of memory wasn't necessarily a big problem, but by the time 3DS and then Wii U rolled around they were prominent issues. The 3DS thankfully supports standard SD cards and you can get a lot of content on a relatively cheap card - or the one packed in with the system - before it fills up.
The Wii U was the system where the clash between Nintendo's budget-centric approach and the nature of modern games began to emerge. The 'Deluxe' model has 32GB, which won't get you far, but the 'Basic' 8GB model leaves users with just a few GB by the time the system gobbles up space for its day one update. Basically, if you have a Wii U and want to have even a small download game collection, you need an external hard drive.
The 8GB limit on the Basic model - which dropped off shelves after a while due to minimal demand - was a peculiar and very 'Nintendo' headache for developers. Oddworld: New 'n' Tasty was a title that took a long time to arrive, and at one point the developers highlighted the issue of the 8GB model - basically, it was tough getting the game small enough to theoretically install it on the white system without needing an external hard drive. Of course, most people had / have a hard drive connected to the Wii U, but the basic principle was that download games tried to meet the criteria that anyone with a system could access the game.
Nintendo fans often focus on the Nintendo example and pooh-pooh third-parties complaining about hardware constraints. The argument goes that a game as small to download as Super Mario 3D World on Wii U is an example of what can be done, so others should follow suit. That's not always fair or sensible, however - Nintendo develops custom tools for its hardware and knows it inside out, other studios have their own engines or the likes of Unity / Unreal to utilise and don't have the resources to reinvent the wheel for a port. It's too lazy to blame third-parties for disc space hogging games - unless more context justifies the criticism - when they're often just trying to make their games work any way they can.
Anyway, one key point prevails here - if you didn't want to spend out on SD cards for 3DS or a hard drive for Wii U - especially as the latter could just bite the dust anyway, as I can attest - you could skip past eShop goodies and focus on physical retail games. Pop the disc or cartridge in and play, even if Nintendo offers optional download packs to speed up a beast like Xenoblade Chronicles X. That's how it should be.
So even though the Wii U data management options are garbage and external hard drives can die, your discs are there and you can play your games. One way or another the Wii U has the memory and capability to take a disc and play it, even if it insists on a download for updates etc. Yet with the Switch Nintendo has seemingly either a) gone off the deep end and thought 'screw it' with memory / data concerns or b) been caught out and put out shorthanded hardware. Basically, some boxed games will require a microSD card to access the full core game. I re-read the quotes a few times to be sure, but there it is.
This feels, to me, like the daftest issue with memory since the Vita, a system that surprised me out of the box. The Vita used bespoke memory cards (which was a bad move by Sony) which were pricey, but I was lucky and got a deal on an OLED model with a starter kit, including a humble 4GB memory card. The system itself had a crazy 1GB of on-board storage, which is Sony's way of saying 'buy our memory cards you cheap sod', so I took my 4GB card and installed my free download of Uncharted: Golden Abyss. It was a beast at about 3GB if memory serves, taking a huge chunk of my storage; I enjoyed it and then deleted it, as it severely limited my download options.
The Vita situation was bad because the memory was custom to the system and - early on - was over-priced. Yet this scenario with NBA 2K18 on Switch is different entirely, because the clear guidance is that if to date you've simply managed your system memory carefully - tough. Unlike with the 3DS family you don't get a pack-in memory expansion, and microSD cards - combined with the bigger size of Switch games - are more expensive than SD equivalents. Some, then, may not have taken the plunge yet, reasoning that they have the retail games on cartridges and have room for a few download-only games on the system memory.
The issue with Switch, in addition to its limited 32GB of storage, is how it uses that space. You lose a chunk right off the bat to system updates and processes (as you'd expect), and the moment you put in a microSD it starts using that automatically. The sticking point driving the NBA 2K18 mandatory card issue is that things like save data and updates naturally swallow up space, and we have limited power to manage our data. I've highlighted in the past that Data Management on Switch is a bit rubbish, as it doesn't let us move stuff around or target specific data in a useful way. The NBA 2K18 workaround, necessitating expanded memory even with the retail cart, is a base covering exercise as the realities of modern game design clash with Nintendo's cost-cutting efforts with on-board memory.
I think it's fair, on the one hand, to question why a game like NBA 2K18 can't fit as a full core game on the cartridge, and it's reflective of two things - perhaps the cartridges are too small in capacity or Nintendo has let 2K cheap out on low capacity stock, and it reminds us that demanding modern games aren't put together in a consumer-friendly way. Those that game exclusively on Nintendo hardware may not be used to it, but anyone with a PC / PS4 / Xbox One knows very well how massive games are put out in a sub-par state and are then bolstered by meaty updates. These updates are often huge in size and it's a modern inconvenience. On top of that, consoles like PS4 basically treat discs as unlock keys anyway, as they dump huge amounts of data on the console regardless.
In some ways, then, the Switch is delightfully user friendly in most cases. Yes there are downloads with physical copies of retail games in the form of updates, but to date they've often been manageable, and you pretty much just pop a cartridge in and start playing; your storage isn't clogged up with the entire cart's data, as would happen with a PS4 disc. Breath of the Wild, with its updates and DLC, has only taken up 433MB on my microSD; Mario Kart 8 Deluxe, just 32.8MB.
Yet we're seeing the flipside, with Nintendo hardware not catering to the modern games it wants to host. Yes, we can legitimately make complaints towards third-party developers making mandatory storage a problem, but the buck stops with Nintendo. Can you imagine the uproar if someone bought a brand new PS4 with a disc copy of Uncharted 4, but then couldn't play it until they hooked up an external hard drive or replaced the one in the console itself? Now picture the scene of someone buying a Switch and a couple of games, and one of those games requires storage that isn't in the box. It's a sloppy bit of product management, because you're adding to the day one 'mandatory' expense, even if the boxes are marked clearly. In a world of affordable, diverse and competitive technology it's a daft hindrance to give the system, even if it is the very definition of a first-world problem.
Most reading these pages likely have a microSD card, possibly one with a high storage capacity. But not everyone's put down $60+ for a microSD card, not all consumers feel the need to do so. But now it's an extra thing to buy, a restriction to work around.
This on a device released in 2017.