What I was getting at can be reduced to a single word — a single letter, even: C. The fact that any software is written in C (or C++) is IMHO sufficient proof that the developers care more about performance than they do about anything else.

I think that still holds even if they demonstrably do not care about performance all that much! You are quite right: current software is heavier and slower than it used to be and than it needs to be; it is also less safe and is more difficult to develop than it needs to be.

The popularity of things like Java or JavaScript is another disfunction: although they are very different from one another, they are similar in that they have poor syntax, frighteningly bad ergonomics and poor semantics. They require too much boilerplate (in very different ways) and are insufficiently expressive and powerful. They are not even as much safer as they should be, given their memory safety!

Our industry is appallingly immature.