Now for teams maybe you need to have a web framework but to say that makes things easier to understand is largely unproven, every project/product gets hairy over time, I have seen it more actually on Angular/React/Vue/Svelte etc sites than vanilla js.
Long term, maintaining a web framework, especially after the hype is gone, is always seen as more verbose and bloat as well as a maintenance nightmare. One day your web framework that made it "simple" will be a complexity spot and maintenance area you will see as a chore where other devs don't want to deal with it and the true complexity will show. Maintaining a javascript only site long term is much, much easier than a framework. In many cases javascript is supported much longer than frameworks that had their hype cycle fade.
In the meantime the abstraction of the complexifying web framework took you away from learning the actual simpler standards and framework, web standards, javascript and the parts of that actual framework.
React for instance jumped ahead and front ran WebComponents and ShadowDOM, those are both part of the browser and standards now. The killer feature phase of React is over.
If it's been 5 years, you'd have to rewrite it anyway to use whatever the framework of the week is. I'm only half joking. The shelf life of a lot of these frameworks seems to be 5 yeas.
It speeds up development and increases the ease of adding new developers.
If you’re being paid, it makes sense to not waste your time solving the problems that frameworks would solve for you.