The beauty of it is, back in 2000 and 2001, 512MB was a LOT - enough that Windows 2000 only used about 15-20 percent of it at max. Often, the computer would idle with barely over 10 percent used. We could say that Win2k was efficient, but I think the more proper word is "sparse" compared to what we're used to nowadays.
When Windows XP came out, however, that all changed. Many of us got the beta, and the Computer Science department even got full copies. It was new - shiny and pretty, though it didn't seem to me (as a more casual user at the time) that all that much outside of a prettier start bar had changed. Well, the start bar and my now newly devoured RAM - XP took up over 100MB of my precious 384MB at idle, cutting into "precious" free resources.