I dunno, my Plasma 5 desktop is lightyears more functional than any DE I was running a decade ago - though I do agree with sibling comments that the RAM delta is probably more to do with pixmaps and pointer sizes that code bloat.
There is also the case to be made that RAM is made to be used, and that half a gigabyte is a perfectly reasonable amount to allocate to a snappy desktop in a world where even the lamest new computer has at least 8.
Sure, I agree that 600+ MB of RAM use is not a big problem for most people, but the context here is in the comment I was responding to, which pointed out that it's not much more than the "lightweight" DEs, so you might as well just use Plasma.
My point is that that's a recent-ish change, the lightweight DEs used to use less than 150 MB of RAM, and it's rather surprising how much the gap has closed. I don't know any truly lightweight DEs; to get small you have to use a tiling WM like i3 or sway.
There is also the case to be made that RAM is made to be used, and that half a gigabyte is a perfectly reasonable amount to allocate to a snappy desktop in a world where even the lamest new computer has at least 8.