Wrote some tools in php + html + vanilla js, around 15 years ago, still in use, with ZERO work to maintain them.

Wrote some tools in the last 4 years in the new fancy js ecosystem, and have to update them them permanently, migrate to new version, and and and.

I am sure, i did something right in the past, but i don't now what ;-)

The churn back in the backbone.js/Ember/Knockout generation was much higher. Seems to have mostly stabilized on React, Angular, and Vue, all about 10+ years old now. Though major versions of these admittedly can add a lot of breakage. (Angular 1 to 2 was devastating for many people).

Of the alternatives, Svelte may be the biggest, and is 6 years old.

Web Components are also a decade old concept (implemented to some degree for several years).