JAAS and CAS were also secure until black hats started to look into them, and since they are beyond repair, have now been thrown away, replaced by OS containers and multiprocesses.
You get similar guarantees to hardware checks with less overhead thats the point.
Either way you're going to want to pay bounties for bugs hardware or software. Security work is never done.
JAAS and CAS where not SIP, I am not sure why you keep trying to conflate them.
It was abandoned in 2006 and SIP were never validated in production under real attacks.
Even Midori had more real use, having powered Asian Bing subnet for a while.
To worship it in 2021 is just theory without pratical results.
Again Midori used SIP's so it was validated in production, right?
Projecting worship on to me is not productive, no need to be childish about this. All the points you bring up for software isolation exist with hardware isolation, formal verification could help both and there is a lot of work in that area.
I think software needs to become safe by default, the endless buffer overflows need to stop. If you then take the stance user land software must be written in a safe language then the need for hardware isolation might not need to exist in it's current form and thats very interesting to me, thats all.
SIP are a form of multiprocess designed for safety and stability reducing exploits and potentially scaling across clusters. Singularity and Midori heavily relied on message passing for IPC which would have allowed cluster scale out.
These where research projects there was plenty the security work available some of it I linked. Much of the work revolved around verifiability of the code to guarantee no cross process breakout without hardware checks.
How do you assert hardware checks can withstand a black hat attack? They obviously haven't been lately.