Comment by tjansen

There is an easy explanation for this: developers optimize their code when the product owner tells them to spend time on this. The product owner will tell them to optimize when product owner notices that the software is getting too slow. When new hardware is released, slowdowns that would be visible on older hardware won't be easily noticeable, so programmers will work on other features rather than optimizing code. Until the code becomes too slow to run on current hardware, then they work until it becomes usable again.