Adding 20% to a 10 second operation is a lot longer on a wall clock than adding 20% to a 1 second operation.
If I could get a micro kernel with a better security profile than Linux, that doesn’t sound so bad. I could easily be using a ten year old chip for my day to day browsing and probably wouldn’t notice.
I'm not sure this holds today. One example I can see is related to crypto. We used to have specific hardware for computing cryptography functions but it's now handled directly in standard hardware and the software has not evolved ( but it's been faster and faster to compute checksum functions )