Been away from this thread for awhile...
Samadhi, I strongly suspect the "famous library" DG was referencing is a recent strings library from a "directional" company. For me that library is one I would never purchase (laying aside the fact that I prefer VSL sounds for my purposes anyway), as my recent computer could barely even begin to run that library. For me, there is no point to buy a library at this time that I could not run without major additional computer expenses.
For those running large templates using VSL full libraries on one computer, 24 gigs is very common, while 48 gigs is not unknown. For the SE libraries and a just a couple full libraries, 12 gigs can work, for SE alone 8 gigs.
As a PC person, I honestly have no idea to what extent you can upgrade your Mac or not. At the very least since you have 20 gigs of ram, I would guess you could at least get to 24, and that might help. As for VSL's corporate policies, as it is their company, and their financial investment, they have every right to do what they believe to be in their best interest. As customers, we can either accept that, or not.
Would I selfishly (note: selfishly) wish things were a bit different? Sure. But as a customer what do I actually receive? For starters, I receive what I think is the best software platform. Given my interest in classical orchestral sound, I also receive the best sound samples for my purposes. Do I wish I could afford more of them? Yes. But, I can be grateful for what I do have, and what it is possible to do with what I do have.
IMO, there are, at present, two main ways to work with VSL (this may change with MIR Pro): 1) using one very powerful machine using MIR; 2) spreading different libraries over multiple machines using VE Pro/Vienna Suite.
IMO, might you be running so many libraries now that you need to have two machines to run all you different libraries? Very possibly. It is not unknown for high-end composers to still need several different computers to be able to use all their libraries (obviously including others than just VSL). Even with the "multiple install" libraries (like that "directional" one), the user still has to purchase multiple dongles. That is simply reality.