I am in IMIT, and some of the systems you're talking about (but not naming, thanks!) are probably in my scope.
The way we do things is at least 10 years out of date and there's no way to convince everyone that we should adopt best practices in the industry (IT, not semiconductors). There are varying reasons, but a majority of people are resisting it.
My team is still made up of GF employees, but the IMIT dept. just went through outsourcing. My experience so far: I recently submitted a request and it took the outsourced guy 4 tries to get it right. I have another request from summertime that I'm still waiting to get done, even after several escalations.
Our managers have promised us dedicated time to continue education and work on projects we're interested in, but it makes no sense. Why? Because we're short-staffed and already put in 50+ hours each week. We tell our managers we have no time to do things, and they make these types of promises. Talk about bad faith.
And to your point, for one of the systems I support I can clearly see performance degrading over time. But it's not broken, and people aren't complaining... yet. Why haven't I addressed it? Let me use the phrase everyone else was using last year "the squeaky wheel gets the grease".
Our systems are such a patchwork that if you dig into system A, it might take you though system B to system C, D, E etc. Each system owner is probably different and their motivations aren't the same. This only promotes the reactive behavior we see "if it's not broken, don't fix it".
Also, there's also a revolving door of IMIT leadership. Don't be surprised when a bunch of level 10+s leave after their vestment period. They join, see the dysfunction, then leave when convenient. And look at their recent decisions: microsoft teams/365 and outsourcing. I'm sure they got burnt for those.