Moore's law moves sideways
3 Ghz chips have been around for years now. I guess there must be major obstacles to getting 4+ Ghz.
So as to keep Moore's law, Intel and AMD are moving sideways and adding more cores, this is good, but faster cores would be better. The multi-tasking is improved but if you have a decent scheduler (aka Linux or mac(bastardised unix) ) then this isn't a problem.
How many people know how to write multi-threaded programs? It's difficult even within a good framework. Many software vendors are going to have to redesign the internals of their programs if they want to keep up.
Moore's law stays for now....but I bet most vendors would rather faster single cores.