I think alot of it comes down to the fact that the internet, and frontend-development (web development mostly) is relatively new. And as with anything new, the community is just trying everything they can to make it work until something eventually sticks.

As someone who has done this for a while, I remember how difficult it was to try and build a UI using flash, then later with just html and jQuery, and now with modern libraries like React. So while it seems like every year there is a new "better" way to do something, but that is mostly because is is getting better and easier over time.