I don't think everything falls on Shimbori. After Itagaki left, not only did Team Ninja change, but the industry also did. Multiple ways were developed to basically exploit the gamers. It became a way for publishers to make additional money. And for every system like loot boxes or costumes or whatever else that was developed, it took away from other things in the games. So basically games got worse, got more expensive if you wanted to have everything, and people still bought them... There was no incentive to stop doing it, where it escalated to a point where people had no choice but to notice...
Developers basically had no choice. Their publishers wanted additional income/revenue, and not complying would mean a studio close down or not having a publisher at all. Publishers didn't know what else to do either, because increasing the price of games was always in poor taste in the eyes of gamers.
Hopefully, with the introduction of things like Gamepass, these shenanigans of exploiting players can take a back seat, and developers can focus on the actual game...
All the best for Shimbori. I have no doubt he did the best he could. Sometimes, that simply is not good enough, and it can be entirely out of someone's hands.
I still think we have not gotten to the potential that DOA has. Including PC was a step in the right direction (although messing up DOA5 on it wasn't great). Whether Shimbori is there or not, there is still an opportunity for DOA to show its potential, and I hope we get to see it.