Although you are of course right with the intel milking its customers, the technological limitations aren't just an excuse. The main problem is the low hole mobility in silicone, which is a physical limitation and can't be solved in silicon transistors. That's also the reason there isn't a 10 GHz CPU, well that and the terrible efficiency. Another thing is that we can't really shrink the cpus anymore. The distance between two atom layers is 1.5nm (which would be hard limit for any shrinking) and there are severe problems way before that, so I doubt well go anywhere below 10 or 8nm. The only thing to look forward to is shift from silicone to some other material, like GaAs, where it could be possible to effectively clock the CPUs higher (into the 10s of GHz).