Reminds me of something Seymour Cray (allegedly) once said: "Anyone can build a fast processor - the trick is to build a fast computer around it". Given the performance boost an SSD gives, I imagine there's some room left for improving overall system architecture without increasing the clock speed of the CPU or replacing the CPU at all.
I think that you would cease to see any acceleration from increased clock speed unless you also sped up other parts of the processor / computer.
I think your sentiment is correct. If we can take advantage of higher clock speeds, then why not do it?