As much as I don't like React, it is here to stay. But even if it weren't, it would still be a better idea to use something existing than writing your own framework. It is documented, well tested, easy to integrate with other tools, has devtools, and lot of developers already know it (and will still know it several decades from now).

Writing your own framework is almost never a good idea. It is only a good idea for the one writing it because we like tech and we like to show how good we're at building things ourselves. Business wise is the worst mistake ever... unless you're Figma or something like that building something radically special, I don't see how this is a good idea.

You have the first example of this problem in the post itself:

"...We did lost something with this choice. First, we lost compatibility with a couple of tools that we really wanted to use. One of them was storybook, that is a super-nice preview system. We had to develop our own frankenstein to do the same...."

The more your project grows, the more of that you will get. Then one day the people that took this decision leaves the company. And then the new joiners are stuck with an undocumented, failing, spaghetti frankestein mess they have to work on day to day.

And finally...those "few simple" components, will evolve...and sooner than later they won't be neither few neither simple anymore.

React was released in 2013 and it's been the top framework for awhile now. There's a strong possibility that React will still be one of the top frameworks if not the top framework in 5 years still.

The Lindy Effect is real.

Doubt. React is here to stay. This is about as grounded in reality as people 5 years saying Ruby on Rails and Django would be gone today.

Gone, no. But both seem to have distinctly ebbed since their peak (especially Rails).