We've entered the age of 64-bit computing. Well, at least most of the new computers have an OS and a processor that are capable of 64-bit computing, but nobody's using it.
And with 64-bit address space, we finally break through the memory limit to use 4GB (otherwise capped @ 3GB by Windows XP, for a somewhat related, somewhat unrelated reason) and 8GB and beyond.
But the performance reviews of games still show that 2GB is the sweet spot for price-vs-performance - games are still happy with 2GB of system ram and increasing further yields much less benefit.
Thinking about the 32-bit Win XP, a reason flashed across my mind.
Windows XP allows each process to use a maximum of 2GB of virtual address space.
And most games are written to be compatible with XP since a lot of people still use it.
So...... 2GB limit it is.
The good part is this shows that current-day programmers can still make efficient programs, if they want to, or have to now.
The bad part is this shows that games are super bloated.