You don't need complexity until you do.

Our company needed an internal tool, and they wanted remote access to it, but it was basically just a tool to generate a file based on a few inputs. We already had a command line program for it, so I wrapped it up in a web server and had it take input as a form input without any JS. It worked great for years, and then someone got tasked with updating it (mostly just combining it with other tools). He couldn't figure out how it worked, so he rewrote it to use a ton of JS, using Angular and other stuff. And guess what? He took longer to rewrite it than I spent the first time and made no functional changes besides some CSS and a ton of JS.

With all these fancy new frameworks and browser features, it seems that many developers have forgotten (or never learned) how to do things simply. Frameworks and browser features have their place (I built an interactive HTML5 app as my first project at that company), but they're often completely unnecessary.

To be fair, in my experience rewrites always take longer regardless of technology choices. You are often reverse engineering requirements which is really consuming both in time and energy. That said, I agree with the point you're trying to make though (I strongly prefer software with less dependencies/frameworks)

Also, he apparently had to update / upgrade the application, so it's kinda to be expected that he will take longer for this.

Yes one should assume most frameworks will be dead 2 years from now. Dependencies problems suck. And create security holes. When development starts going into the cloud get ready for a lot of pain the world has never seen before.

It depends on your needs... Are you building a complex application with several developers. You probably want a build system and module based JS. I prefer react + redux + material-ui. Some of the new stuff around hooks and context could displace redux for smaller apps easily.

If you need a one-off page that does a little dynamic stuff? Drop in jquery+bootstrap and a little wiring js and be done with it. Not a huge fan of the size of jquery + bootstrap, but it's a fast path to done depending on your one-off needs.

My brain hurts just imagining this.

Mine too