I hope to move to TS in 2025
But, we still don't use a frontend framework, we just write components as classes. Each component takes a root node that the parent is supposed to "own", and that's kinda it. React is more productive short term, but I find this easier long term with complex UIs, keeping memory usage low, and less work keeping stuff upgraded.
It's basically a home-spun version of backbone, and the reason people don't do that so much anymore is the same that backbone fell out of favor- you don't naturally get composable components without lots of manual management and excess paints and reflows.
It's certainly possible to build what 75% of websites actually need with this approach, but I wouldn't consider it for a moment for any UI that I actually consider to be complex.
The only way to do home-spun stuff in JS/TS is to narrow the use-cases and components down religiously. The moment you'll require more than 2-3 bits of the website to interconnect... take one long hard look at the future and avoid the headache of writing your own JS boilerplate.
I love eschewing JS frameworks as much as the next man, but I also love my free time. Too much to waste it debugging problems coming from hundreds of different user stories and approaches. React's mature enough, as are most of the big libraries commonly leveraged on it.
React is on like version 18, you guys can keep getting paid to upgrade frontend libraries every year, I'll watch.
Mature software doesn't break things every other year.
As an illustration, try to make a website that has 1000 drag-and-drop elements that you can drag around the page. Getting it to render at 60-120 fps is hard and fragile.
Glad I always avoided react then, despite all the hype.
It really hasn't been a productivity issue for me... I wrote all of fastcomments (uis, backend), so... :P