Something that's too big today will seem trivially small soon of course.

Those giant 800k floppy disk games, those really amazing 160x120 QT movies at 8fps, remember how colossal Myst was, a whole CD-ROM!

I remember getting 1 mb of memory for my 386. A whole megabyte of memory!

(Firefox is usig 110mb at the moment - I started it about five minutes ago.)

There are other constraints on the size of a program, though. All other things equal, larger programs tend to be harder to maintain, and proportionally buggier. This is completely independent of the cost of memory, the size of processor caches, etc. -- There's nothing like Moore's law affecting the human brain's ability to understand sprawling, tangled code bases.

Also: Bugs in device drivers tend to affect stability much more than in userland programs.