I like your take that human tolerance is the limiting factor. I'd agree that is a major constraint. The rest of it is just economics. When I started program

I like your take that human tolerance is the limiting factor. I'd agree that is a major constraint. The rest of it is just economics. When I started programming, people I learned from would optimise code in assembler, use clever algorithms and write highly unreadable code that was impossible to debug. One bit of code I remember interleaved various operations so that it's access would line up with disk reads. I rewrote it to just hold the data on memory. It wasn't much faster than his disk based code in practice. But the only reason to go to that kind of effort was the severe constraints hardware placed on software. When those are largely removed, the imperative is to write code fast that other people can still understand.