>>723533260
It changed after 3, when Nagoshi publicly apologized for the writing (japs hated the political part) and promised to take a step back. This one is something I'm not going to find with a quick search because it was scanned from a printed magazine, I found it on a jap blog before. But anyway, that was the point where he gave more creative control to his studio leads. Yokoyama jumped at the opportunity and delivered some of the most retarded stories to date.
What happened after 5 was that the studio grew too big to manage and many employees started naturally splitting into preferred camps. Right before Judgment came out Nagoshi confirmed that they're internally split into two teams, one under him and one under Yokoyama. Plus flexible employees who didn't have much of a preference and moved between them as needed.
Then it was just a series of Nagoshi's fuckups as Sega's board member combined with him being tired of having a bloated team to manage, he was gradually giving up on this shit, spacing out. I don't think it was ever disclosed when exactly his parents passed away, but their deaths pushed Nagoshi to make Judgment, that's his most personal game which I don't think he'll ever be able to top.
Come to think of it, the pre-production of Yakuza 3 probably happened shortly after he tried to reconcile with his parents, only to find out they're not really there anymore (Alzheimer's).