At the time, it was suspected some big changes were going on behind the scenes at Sega ahead of Sonic's 30th-anniversary celebrations. While this may still be the case, the voice actor says it was his decision to step down from the role.
He recently shared this information in an interview with Voices from Krypton (transcript courtesy of The Sonic Stadium):
“I think my response would be “it’s just one of those things.” It’s a time in looking at the way things are being handled and the way that you are, where you’re at, and what you kind of want to deal with, and do. And I found myself going, ‘I think it’s time. I think it’s time to be done.'”
"I know people are sort of surprised and shocked by it, and it was like “yeah”, and I’ve seen all the speculation that were like, “voice actors don’t walk away, he was fired!
It’s interesting the perception that people have, and we get this all the time; like, it’s amazing how all the experts that are out there that have nothing to do with this industry that make all of these assumptions, you know, ‘this is how this works and this is what this does’…
You know, after a while you do things and start going ‘I think I’m very pleased and I’m very proud and I’m very happy with what has happened there,’ and I think it’s time to say, ‘I don’t want to keep doing this.’
Some people would be like, “why?” and it’s like, “it doesn’t have to make sense to you.” It’s perfectly good sense to me and it was the right thing to do, and I’m happy to have done it.’"
Smith's departure from the role was followed by Tails' voice actor noting she wouldn't be voicing the character in the upcoming Netflix animation, Amy Rose's voice actor also revealed she was done and Mike Pollock confirmed he would continue to voice Dr. Eggman in future Sonic games.
You can see Roger's parting message (and Sega's goodbye message to him) in our previous story.