[jimnotgym]

> Take a computer that used to run Windows 2000

out of a museum, or a skip perhaps

>and install KDE on it

Then put Windows 10 on it, or any other fully featured modern GUI OS. And we have proved what? Computers from 18 years ago don't run modern OS's very well, but can run ok with an OS specifically pitched as 'lightweight'.

On the other hand I have a PC right here on my lap that is 10 years old that is running Kubuntu problem free.