I can give you an example: in the Bitwig digital audio workstation, you can choose whether external third-party plug-ins (small audio processors) are in the host process or in external processes communicating through shared memory. I just tried with a very simple plug-in (3 band EQ) to see how much I can stack in either case:

- In the "in-process" case I can stack ~1400 plug-ins on a single channel before I hear a crack in the sound.

- In the "shared memory" case I can go up to ~200 at most. And I'm confident that they really did the very best things possible for the implementation to be performant.

So for me the "things isolated in their own process" means literally getting seven times less out of my system than in the host process (and that's frankly unuseable, definitely not "negligent").