You don’t need big frameworks or component madness that’s more of the same.

You don't, but in any sufficiently complex app you'll end up writing a sort of 'mini framework' of your own as you abstract all the things that crop up more than a few times. That framework might be really nice at the start but it'll get more and more hacky as the project continues, especially if you're constrained by resources. Eventually you'll regret not using something standard.

If there are more than a couple of developers on the project it'll be something no one really likes after a year or two.

If there are more junior developers it'll be a reason for them to want to get off the team because they won't want to be a part of the 'old legacy code'. Then it'll be hard to find people who want to join.

Eventually, as it gets harder to recruit people to the team because it's on a weird, legacy framework that no one knows, there'll be a big project to refactor it on to something more standard. That'll probably be React. At the same time most of the senior developers will be calling to scrap the codebase entirely and rebuild it (wrongly in almost every case, but they don't care and want a greenfield project to play with new things on.)

This is a story that has played out at every large org that builds apps internally, and probably a lot of startups as they mature and need to hire more devs. You might as well skip all of it and use a standard framework from the start.

This has never been true for me. I never end up writing any kind of internal framework. Instead I write libraries that solve specific problems and achieve code reuse, which are really either functions or data storage objects restricted to their own files. At least, that’s how I think about code universally, libraries, but specifically in the browser this comes up less because the problem space is much smaller. Really in the browser it’s all about organizing code around event handling and putting text on screen. Let’s not over think this.

Anyways this idea of internal frameworks has always been weird to me. Nobody says this of code outside the browser, so why would they say this inside the browser? When I think about in those terms this clearly becomes a simple organizational problem and I don’t need a framework telling me how to organize things like a parent telling me to do chores.