Is it true that those streamlined Wiis actually can run Gamecube discs but you just can't actually play them because the lack of GC controller ports and memory cards?

I've heard about that, but I can't confirm it as I don't own that version of the Wii.

Obviously.

When you want cutting down cost on such an "outdated" console, why go through the trouble of creating an entirely new disc tray input thingy, when you can just remove all things GameCube related to cut down cost?

I question why they would keep the internal equipment and programming required to run Gamecube games when they're taking everything else out, but Nintendo's done crazy things before...

While I'm yet to see one of these updated Wiis in real life, I'm assuming that they're about the same size as the original Wii. In that case, it may well have been cheaper for Nintendo to just use the same motherboard in the new Wii but not include any of the extra internal connections etc. required for GC functionality.

That way, they'd save on the R&D costs of redesigning the board (although that could be outweighed by the cost of including redundant components in every model - I don't know enough about the innards of the Wii to judge how much redundancy would be there).

If that's the case, then I guess the Wii would boot into the GC game but be unable to use it. While it'd be quite odd, and I'd imagine that Nintendo would put in a check so as to avoid confusion, I guess it's in the realm of possibility that this could happen.

Everyone is getting it mixed up. The new wii no longer plays wii games, but is now offering enhanced gamecube capabilities.

Actually I think my cousins wii is a newer one, I'll check it out next time I go over

Actually, Im pretty sure it won't. Mine is never able to read the disks, no matter if it is GameCube or Virtual Console

I'm speculating, but it wouldn't be difficult for Nintendo to have slightly different firmware to recognize GameCube discs right away and not let them work if the GameCube controller ports aren't present on the Wii in question.

I have one of those updated black ones. It has no Gamecube controller- and memory card ports and it is not able to read Gamecube discs. In the disc channel it still says "Gamecube" and "Wii" but this is due to the fact that they only have one OS for both versions of the Wii. I have tried it. After inserting a GCN mini disc the console makes a rattling noise and spits it out. Wii discs (no matter if they are single- or double layered) run, of course, fine.

That's odd, all references to the Gamecube are removed in the Wii U's Wii mode.

Well, I'm assuming they're actually putting effort towards the Wii U's emulation, while the updated Wii was just a cheapening of the original product and any expensive changes to the OS would be a waste of money.