Uhh, unless SSD technology changes significantly that line is a long long way off. SSDs are orders of magnitude slower than RAM. For example assuming a 2 GB/s speed is legitimate, RAM is over 22 GB/s. Plus RAM can be written and re-written without any wear, whereas SSDs have a max-write limit.

Right. Plus when you power off RAM ... Oops!

I think it's supposed to happen with these: http://en.wikipedia.org/wiki/Memristor

HP is working on a new architecture based on computers with just a buttload of persistent RAM, but so far it's vaporware.

Supposedly they will never sell this computer, only renting access as a "fast cloud".

I would think the recent historical tendency is to have more cache levels, not fewer. This would only happen if the cost of storage loses its sensibility to speed.

No. Swap or paging is unused RAM "saved for later" (to free up real RAM space). It is never accessed or modified directly from processes except to push it back into RAM when a process requests a memory region which has been paged.