My best guess is the GUI is somehow really heavy, wouldn't expect a simple console program that connects to some weather API to require that much RAM. But I never worked on apps like this, so no clear idea.
I also like the weather icons being 4K and having some smooth anmiations.
Not to say that it's gone worse (it has IMHO) but comparing 25 years ago to know doesn't help much. Times were different back then. That's like comparing 1900 travel to today.