Processes were a form of robust virtualisation once. It’s just pushing the problem down another layer. There are vulnerabilities in virtualisation layers too.
> There are vulnerabilities in virtualisation layers too.
Qubes OS v4+ does not use typical software virtualization methods. VT-d hardware virtualization it uses was broken only once, and it was done by the Qubes founder: https://en.wikipedia.org/wiki/Blue_Pill_(software)
Was it ever robust? Or just that there weren't yet so many exploits?