Even before OS'es supported that much people were sticking that much RAM on expansion bus cards and plugging them in and treating them like fast disks. So it is

Even before OS'es supported that much people were sticking that much RAM on expansion bus cards and plugging them in and treating them like fast disks. So it is going to happen either way. The performance boost for the DB is just too much compared to it thrashing disks constantly and there are quite a few benefits to having fewer machines compared to many DB servers as well.