I'm a little puzzled by this fascination with shared memory concurrency myself. If you have to scale beyond one physical instance, and you generally do if you have to scale at all, your scaling mechanism is your distribution mechanism. Of course, there are apps that need maximum throughput in a single address space but they seem to be very much in the minority.
That's like suggesting that you can eliminate CPU cache because most resources are going to be in main memory. Few systems scale 1:1 when adding more systems, yet making each system more powerful has the potential to be more useful than increasing the scaling factor.
In other words if 100 machines are 60 times more powerful than 1 machine, increasing your scaling factor is less important than doubling each machines throughput (assuming you keep the same scaling factor).
