That is not true. You mentioned Virtua Fighter in comparison first and I was trying to defend that and point out that it is different.
I am not trying to discredit Puyo Puyo as a good series or anything, I am just saying that it's continued quality has more to do with them not changing anything major and that it would not be fair to list every game in the series Sonic Team made as proof they are making as many good games as AM2 or whatever you meant by that. The same is true with the Phantasy Star games for the most part, not much of their gameplay has been altered for 10 years. Neither of these are issues, mind you, just saying.
Sonic games for instance have quality ranges all over the place, but they do change pretty much everything for each release. Something like Shadow had very similar controls to Heroes and very similar art to Adventure 2, but had entirely new gameplay styles and gimmicks. All of this pretty much sucked, but they DID try new things.
I disagree that a master of Puyo Puyo Sun may have any troubles in Puyo Puyo Fever though. I know a guy who plays the series like weekly and masters each release the second he plays them. The same is never true for Virtua Fighter, even with some of those really crazy talented guys.
I would say another puzzle game such as Columns would have been a better comparison than VF.