There is probably some low hanging fruit to be harvested in terms of memory optimizations, and it could be a selling point for the next while as the memory shortage persists

You work on both. Sometimes you need to prioritize one, sometimes the other. And the benefit of the second option is "it makes our product higher quality, both because that is our work ethic but also because our customers will appreciate a quality product".

The business is only going to care about the bottom line. If it's not slow enough to cause business problems, they are not going to say "here's a week to make software faster"

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.

I agree with this. What you focus on depends on the circumstances. I believe PaulG likes to say that premature optimization is the root of all evil. Early on, you’re trying to ship and get a functioning product out the door — if spending a bit of money on extra RAM at that time helps you, it’s worth it. Over time, as you are trying to optimize, it makes sense to think more about memory management, etc.

That is why we have slow, bloated software. The companies that create the software do not have to pay any of the operational costs to run it.

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.

Why not both ?

Because time, effort, and attention are all finite