Where we're going, we don't need IPC.
This is true on many different levels.
IPC is like horsepower, and in the age of cheap gas and machoism that fed the muscle car genre the product engineering was all about horsepower.
But what followed was that management found out there was a ridiculously larger TAM waiting to be tapped for vehicles that catered to the everyday life of the soccer mom and commuting worker.
I'd wager Toyota has made more in terms of absolute profits on their Prius lineup than Lamborghini has in its entire existence.
Where compute is going is away from IPC (driven by instruction-level parallelism or ILP) and towards thread-parallelism (TLP).
If you (the customer) really
need more performance then you ought to be willing to pay more for it...and paying more for it doesn't mean buying a higher clocked SKU or a higher IPC core design; rather it will mean paying more for a software package that takes advantage of the availability of more cores.
The AMD's and Intel's of the world aren't going to custom build a Dodge Viper to feed a small niche market of muscle-car minded buyers. (they'll leave that to IBM) But they will build designs like Xeon Phi and Seamicro products that deliver a ton of flops for customers who are willing to invest in the creation of software products that can extract TLP.
Itanium is basically the proof, the silly ridiculous academic experiment, into determining whether or not the market is interested in pursuing ILP. The pain that comes from pursuing ILP at nearly any cost turned out to be a bust. The market isn't interested. So TLP is the next best thing.
Soccer moms and commuters everywhere would rather drive a fleet of Priuses than pay for the thrill of their 21st century flying car ala the Jetsons. Practicality trumps all, CPUs are not immune.