How can people make generalized statements like this without anything about the use case or problem that would have to be solved?

You have exactly 0 information available and yet you make a comment like this? Is this why we have cargo-culting?

Not every solution to a problem needs to use as little memory as possible. And also not every solution can ignore memory usage. It depends, of course.

Since this thread is about throughoutput and optimizing for that, I could tell you that most times I've been put in charge for optimizing throughoutput, having low memory usage have been pretty far down the list.