Not exactly, but broadly speaking he is correct. The 92-94 material is is best, Dogg Father wasn't on the same level, then the three No Limit were very underrated (yes, including the first one, but especially No Limit Top Dogg). But from then on it was all downhill with the occasional flash of brilliance here and there
He was very unlucky to have that case right in the middle of the era that he helped define. He could have released another classic album between Doggystyle and The Doggfather but it didn't happen (although it is not clear whether the label dynamics at the time would have allowed it anyway, given how slow Deathrow was with album releases), then when he was free from it, the era was over.