Computers are not getting much faster on a single stream of instructions.
The reasons are:
1. We have reached the point of diminishing returns with pipelining.
2. Switches have not been getting faster, only smaller.
There are new kinds of transistors that have not yet reached the marketplace which will achieve a tenfold increase in speed, and are smaller to boot. Intel has announced that it expects to market circuits containing such transistors in the next few years. So you can expect an order of magnitude boost sometime before 2010.