It's not just that.
Since 2015 was also the start of the GamerGate movement. The toxic feminists and their corporate lemmings declared open war against "toxic male spaces" in gaming. This led to many talented and skilled male developers, optimizers, and graphics engine programmers being pushed out of the studios. Many of these people formed their own indie studios, where today many of these games outperform AAA commercially.
One of the main reasons Unreal Engine 5 is so popular is that it makes it very easy to achieve high-quality graphics with little expertise. You can literally train F-tier nobodies straight out of college and have them use Unreal Engine 5 in a few days. They have no idea how to optimize or use the advanced programming features inside Unreal 5 to do anything novel.
In 2015, women only made up ~20% of the development team. Today, almost 35% are women or "non binary", with many men shifting in politics towards more pro-feminist dogma. There are now more managers and executives in these studios who are not gamers, which leads to bad project management... chasing 8K Nanite everything, unchecked asset bloat, targeting 30 fps consoles while shipping PC ports as afterthoughts, or shipping before proper optimization.
The problem of toxic feminism, where they are dismantling male spaces, enforcing quotas, and elevating "lived experience" over competence, produces worse games.