> Point #2 is very weak, because the alternative to slow sites is spending time optimizing them which may waste human time.

Ehhh the easiest way to get fast sites is combining a fast language and framework. There's like 3 orders of magnitude difference in performance between something like Django and Vert.x

I've seen code slow enough (PHP, 10 req/second) that running enough capacity consumed like 15% of the engineering budget. That could have easily been .1%.

Since developers dont care about hosting cost most of the time, they keep using horrifically inefficient frameworks. I rarely see super slow code because people get called out in code reviews for doing really stupid stuff. It's always the slowness of frameworks that's been a problem IMO.