I've played entire levels in multiple Sonic games this way (at least one on Genesis and maybe two? of GBA ones), so I'm sorry if my experiences with them offends you or diminishes your enjoyment of the series.
And yes, there are some maze levels in Sonic games, obviously that doesn't apply to those levels.
Found the problem. Just hold right is a valid criticism of the GBA games for sure, though they can still be enjoyable. As for the Mega Drive games, is it possible you played the first level or two of one or maybe two games? Obviously the difficulty increases as you progress, so if you want to you can hold right (and miss your chance to get Super Sonic, in most games) to some extent in the first level, but be prepared to defend yourself if you're going to hold that opinion about the games as a whole. It makes it sound like you either haven't played the games much at all, or you're some kind of super player who can magically hold right to win the whole way through, lol. Even I'm not that good!
I know you're saying you've played them a lot, but it's really hard to believe that. And it's at odds with what it seems like you're saying above. I'm not calling you names or anything. Just saying.