As you said, this is a long time in the making. State and Federal funding for universities has been dropping since the 90s and accelerating after 2007. The often talked about toxicity in academia (especially about publishing) is IMO partly just a result of that - it turned into a competition for scarce resources, which ruined a lot of the magic that draws people to PhD programs. Trump's awful shit undoubtedly catalyzed this drop, but MAGA is only a part of the story.