The trend is in what manufacturers have offered in terms of RAM for the last two decades.
128 MB --> 256 MB --> 512 MB --> 1 GB --> 2 GB --> 4 GB --> 8 GB -->16 GB --> 32 GB.
Even Apple offers 32 gigs on the iMac today, which suggests that even Apple realizes there is going to be a need for 32 gigs of RAM on a current 2013 computer; that doesn't sound like RAM usage tapering off to me, personally.
I didnt have 128mb in 1993. I only had 8mb