Simple one-page web apps can be quick to build and free to host.
I consider several of mine “finished” software. They won’t ever need updates (unless browsers deprecate functionality). There is no maintenance burden.
We CAN build software like this now. So why don’t we?
FWIW… things I made:
https://notes.veryuseful.app/
https://veryuseful.app/
https://caniphp.com/
https://golf.pico.games/