Even if Apple could match Intel's performance in the laptop power envelope (implausible), that still wouldn't be enough. They'd have to beat it by a big enough margin to make binary translation feasible. When they switched from PPC to x86, they got enough of a performance boost to make Rosetta Stone work ok, despite the overhead. I'd be surprised if it's even possible to beat the current crop of x86 processors in single-threaded performance by such a huge margin, ever. Let alone beat whatever Intel has out by that time.