> memory is often not a constraint at all

This type of thought process is how we get Electron applications and when several of them are running at the same time they can bring your OS to a crawl by having consumed every bit of memory available for some simple GUIs. Memory absolutely always matters.

Also the people who I see saying memory doesn't matter are usually developers who are running on 32GB+ work stations. They forget about the user still running with 4GB or 8GB of memory.