I think it's important to appreciate that while RAM itself is cheap, the same is not always true for upgrading it. A lot of people these days use laptops where RAM is soldered on, and is not upgradeable after purchase. And they may not have had a choice if the machine was provided by the workplace.

Trying to keep RAM usage low doesn't hurt anyone.

What I personally care more about is CPU usage, because it affects the battery life of my laptops. Why is VS Code using 10-20% CPU when I have it open in the background? This behavior seems to come and go with each VS Code update, even without additional extensions installed.