You can get an old computer to work great with an old OS right up until you ... open the inner OS

Not only an old OS. An older web browser has the same issues.

I think we need to come back to gopher and ftp because http is a rolling target.

But we are https (s comes from encription).

I actually meant a lightweight OS but I guess the parallel construction was so tempting I wrote the wrong thing. Everything seems great until you ask the computer to render the modern Web.

Windows 9x/2x/XP users have RetroZilla as a libre browser. Mac 8-9 users have Classilla.

Linux users can compile gcc 4.x and pkgsrc just fine on any > 2001 distro.

There are some hacky ways of getting a little distance on modern OS's, like using terminal based browsers. I'm thinking Links/Elinks but that will only get you so far and so long as the security certificates are available.

Carbonyl runs pretty well (YouTube videos / WASM powered apps like figma et al) https://github.com/fathyb/carbonyl

I think at that point you're getting away from "good as new!" to more doing it because you can.

"browservice" will render web pages server-side and then deliver them to your browser as an image with simple javascript.

It works in virtually all "old" browsers and can be very useful for older computers.

https://github.com/ttalvitie/browservice

For very old web browsers, WRP works similarly but replaces the javascript with an imagemap.

https://github.com/tenox7/wrp

At that point you have a local energy inefficient terminal that barely contributes to what you are trying to do, and a cloud computer which must be run on your behalf somewhere, both of which require energy. What's the point? At that point I doubt it has any benefit compared to running a more modern machine.

It might give some security benefit similar to remote browser isolation.

But it looks like this particular project is more focused on getting retro hardware usable on today's internet. Which is not a bad goal either.