[Scaless]

You are more or less describing the architecture of the PlayStation 3: https://en.wikipedia.org/wiki/PlayStation_3_technical_specif...

The problem with this type of system is both the software and OS have to be aware of what is or isn't a "main thread" job. You have to architect your whole program around job systems to spread your data between the main thread and sub-processes which was a major complaint of gamedevs for the PS3. There's also the fact that many consumer software developers just don't care and will flag all of their processes as high priority jobs.

It worked out decently well on PS3 because it was such a locked down system, but for a general purpose desktop it would be utter chaos.

[inawarminister]

Wasn't Linux installable in early PS3s, and some labs (US military?) used stacks of PS3s as distributed superishcomputers? I wonder if anyone had analysed general computing performance in CELLs...