Which is kinda stage they don't just combine em honestly. Lock on existed and that's what it did, in fact 3 & Knuckles were supposed to be the same game but McDonalds were going to make some Sonic toys so they decided the project was to big anyway.
That'd be cool. Image if it came with a demo for Mania lol. Games amazing and definitely modern but whould be to old for that at this point. Imagine if Sonic Origins and Sonic Mania Plus came in a bundle that cost less then buying them separately.