The "artistic growth" thing was in response to the question as to why other artists don't go back to their old styles. And sure he experimented etc. but that experimentation got him nowhere. By saying that all the experimentation was wrong, he is implicitly admitting that he should not have developed his style, thereby the decade post-SOTS/Loaded was a mistake.
I think that we are unable really to judge what his best style was, simply because I'm sure there were other factors that contribute to the consensus view that "SOTS is his best", such as production, guest appearances, and also the time when it dropped. Personally, I like his style best on that album, but I'm certainly not as disappointed as most with Lynch by Inch. There also seems to be a nostalgic desire for people to remain static and stagnant, how often do you hear fans complain about rappers having styles different to the ones they fell in love with (Common?). I mean sometimes it is warranted (Andre 3000), but so much of the time I think it is just that nostalgic yearning for what we are familiar with. People change, usually they don't go back. Lynch must have some real regret to claim that he is doing such a thing.
/rant