Javascript and it's ecosystem is changing so rapidly for one simple reason: Javascript and it's ecosystem is easy.
You heard me correctly. Javascript despite it's eccentricities is a simple, easy to use language. HTML, CSS, JS is a simple (relatively) easy to get into stack.
This leaves an enormous pool of developers who are hungry to make their mark in the world, and with technical skills that frankly outpace the simple world of web development. So they start building abstractions. Abstractions are fun to build, prove the builders competency, and often do provide some benefit to their end user.
The story of Vue.js (and Vite) is more or less this (there's a documentary on YT, go watch it). They were working at Google on experimental web projects in vanilla JS. Decided they wanted to build things people actually use. Decided a view framework for JavaScript would leverage their skillset and be of use to the community. Had the technical ability to throw vanilla JS around with ease. From this, comes a framework.