If you ran a business, would you rather your devs work on feature X that could bring in Y revenue, or spend that same time reducing CPU/RAM/storage utilization by Z% and gives the benefit of ???
Likewise engineers are only going to care about doing their job. If the business doesn't reward them from taking on optimization work, why would they do it?
This is not true of all engineers and all businesses. Some businesses really do 'get it' and will allow engineers to work on things that don't directly help stated goals. Some engineers are intrinsically motivated and will choose to work on things despite that work not helping their career.
What I'm really getting is, yes, engineers choose "slower" technologies (e.g. electron, React) because there are other benefits, e.g. being able to get work done faster. This is a completely rational choice even if it does lead to "waste" and poor performance.
If you have to buy extra RAM or pay unnecessary electrical or cooling expenses because the code is bad; it's not their problem. There is no software equivalent to MPG measurements for cars where efficient engine designs are rewarded at the time of purchase.