Good point, pooling isn't currently worth that much in the long term, except in the sense that the instant feedback can be motivating. But it is also worth keeping in mind that smaller amounts may come to be worth more over time if it ever takes over a significant segment of the economy. The higher the value of bitcoin the less tolerable this kind of variance is.

My thought regarding the macroeconomic scenario described is that it would actually result in more processing time available for sale at cheaper rates. This is because the more processors that are already allocated towards bitcoin the more additional processors are needed to make any kind of profit. At some point it becomes more profitable to sell processing time elsewhere due to the cost of electricity and equipment. By this time a highly efficient system for generating processor power has already been developed. One thing that could help the bitcoin economy as well as Folding@home would be a charitable drive that pays miners to allocate processor time to folding instead of bitcoin.

I'm not sure if structured ASICs and other highly customized hardware is as useful for folding as it is for mining bitcoin. However, there are probably a lot of GPU miners who will need something to do with their equipment when they can no longer profitably mine bitcoin.