Overshadowing Sequels

Exactly.

if you say warcraft people think of this

Sonic 06 was what kicked off the "every Sonic game is bad" meme. Something that Sonic is only now 11 years later partially getting over.
Jesus it's been 11 years
The Genesis games may as well have not existed anymore. It didn't matter that tons of people loved, Adventure 1 & 2, Sonic Advanced, Sonic Rush, and, Sonic colors, ect…
Sonic 06 came out then any and all credibility Sonic had when into the trash and the gaming media developed huge hate boner for Sonic games. Only after Generations came out Sonic was barley able to get some good rep again.

The original was a somewhat decent game but its sequel really blew it out of the water.

...

...

No, Heroes started it and the one-two punch of Ow the Edge and 06 just cemented it almost subconsciously. The Dreamcast dying probably didn't help things either.

...

Aside from forcing you to play all 4 teams to get the real ending I don't see why Heroes is considered bad. I'm replaying it right now and i'm enjoying it so much i'm going for 100%
I'll give you Shadow since even though I can enjoy it for what it is, it really is a mess of a game.

The Werehog was shit true, but at the time everyone praised the day time stages.
Sonic Boom was far after "Every Sonic game is bad" was established as the norm
If you wanted you could have brought up Secret Rings Now that game is a piece of shit.

I would say so, I never saw any hate for those games until Sonic 06 happened.

Yet it cemented it even more which is relevant since you complain about meme living that long.
Because while it's a bad 2d sonic game everyone understood that it's fine for what it is(3d bigger world building experimentation) at the time. Since 06 took that concept and trashed all the potential that adventures could have the end result is at least 3 mediocre to shit games that went nowhere.