The whole " make every game series we own a minding numbing, grindfest, microstransaction filled 100 hrs long rpg " mindset ruined them. The feel in their games in general now is just ass. I picked up AC origins on game pass because I at least wanted to try the rpg ac before I wrote them off entirely. I played for 2 hours and dropped it. AC 1 and the Ezio trilogy were simple but the game feel was smooth. The Kenway saga was more flashy but still kept the same groove. Even unity tried to revamp the whole stealth thing in general but now it's " eh, your a warrior but if you grind for hours on end then you can unlock skill to play make believe asssassin."
A lot of blame for this goes to corporate decisions, prioritizing engagement duration over engagement quality, etc, but I don't think enough blame gets levied on developer homogenization. Not the individual developers themselves, but you can't just treat them like factory line pieces.
What companies like ubisoft do is just give a studio projects without much consideration to their skillset, merge studios and exchange staff between them based on efficiency metrics and not game archetypes. What this leads to is homogenous teams with people who have done some RPG work, some Open World work, some FPS work, etc. To an exec or a middle manager, this sounds great - You have all the talent spaces in your team, so you can make anything, right? But what ends up happening is all their preferences, prejudices, and design parameters leak into the project. Given enough time and design work, you'll inevitably end up with a homogenous blob of a game, where the RPG guys solved progression with gear loot, the open world guys tied that in with their solution to world design of a massive world of thousands of things to explore filled with loot, and the FPS guys made sure the combat was understandable for the COD crowd by adding aim assist, lockon, the standard weapon archtypes, etc.
Homogenization of developers is inevitable without strong creative leads at the helm to slap it down and force everyone down one design line. A Kojima, or a Miyazaki (Elden Ring) can make it happen. Most studios have capable leads, but exec oversight and over involvement in the design phase can prevent them from establishing that ironclad design goal when the exec hears the open world and RPG guys talking about thousands of hours of procedural content.