But on the other hand I cannot count the number of times I've seen Angular included for a simple contact form with validation on a static site, React to render a single trivial dynamic list or a nice, but basic JS lib that only works in module form via NPM exports.
Sorry if I sound like a fortune cookie, but it's true - if all you've got is a hammer, everything looks like a nail.
Since 2001 or so, I can count on three fingers the number of variable collisions I have experienced in small- to medium scale projects. That I as a newbie now have to understand and manage various module systems in order to embed a lightbox on my site is a huge jump in complexity for a gain that is at best negligible in practice.
And while you and I probably have worked on some higher-complexity use cases, I think we would be kidding ourselves if we assumed that this constitutes the majority of the web.
Because that's not Facebook-scale, it's the dude around your corner selling dishwashers and reparing washing machines, trying to get his inventories's prices from an Excel sheet onto his page with a minimum of fuzz.
Do they? In most tests I've seen straight javascript / jquery on the DOM is faster. eg. https://objectpartners.com/2015/11/19/comparing-react-js-per...
IMO, the JavaScript ecosystem has matured. Sometimes in weird ways that aren't great, but it's still better to have an irritating package manager than no package manager at all. But there's no price to be paid here - if you don't want to use any of it, you don't have to.