TO clarify - i'm not claiming a 10ghz p4 would be competitive today. I'm claiming that a 10ghz P4 VARIANT in 2006 with tweaks to the original 2001 design, when put on a modern process, up against the other things around IN 2006, would wipe the floor. The plan was to have the p4 running at 10Ghz on the process tech available in 2005-2006. NOT what we have today in 2013.
Of COURSE modern CPUs have better IPC. They have billions of transistors more than the P4, bigger cache, much smaller process tech, etc. The playing field is NOT LEVEL. Put a 10ghz P4 up against a 2006 spec AMD chip (NOT SOMETHING FROM TODAY) and the story is entirely different.
IF that had worked, we wouldn't simply have 10Ghz pentium 4s today. We would have 10 ghz or higher clock CPUs that had additional execution units, multi cores, etc.
But clock speed did not scale any more with process reductions like it had since the early 80s. There was a wall at approximately 3-4ghz, and the current CPUs are of COURSE much better IPC because they were FORCED to be that way because ramping up clock and shrinking process simply no longer works.
And again, the heat the P4 had was a symptom of the CPU frequency scaling hitting a wall and intel having to ramp up power to get the thing stable at even 3Ghz. Recall that prior to the P4, CPUs were only hitting 1-1.3 Ghz. That the first P4 hit 1.6 quite easily (pretty sure people were o/c'ing them to 2+ ghz on release) was perhaps a misleading indicator of things to come.