Five years ago your comment would have made a lot of sense to me, but now you're talking about how everyone's gone X86 during the first massive movement away from X86 the industry's seen... smartphones and tablets are all computers that run on ARM processors, they're cleaning X86's clock in the only rapidly expanding market. And ARM's next core design is aimed at servers.
For the first time, Windows compatibility is mattering less and less as many users only use the web and web apps on their computers - opening the door to competing processors for the first time since the late 80's. At the same time, PC's continue to represent a smaller and smaller share of new CPU's, which are migrating to data centers, smartphones, and pads, which are even less dependent on X86 compatibility.
For the first time, the computational penalty of X86 instruction set translation for RISC cores may not outweigh the compatibility benefit for a significant portion of users. Increasingly, customers don't care about compatibility with existing X86 codebases. Like ARM, anyone with a new processor with compelling performance per watt might actually be able to sell the thing, without everyone assuming it's worthless if it won't run Windows.
Also, I wouldn't quite characterize POWER as a strictly legacy product, since IBM introduced the latest iteration, the power 7+, in August 2012, and is currently selling 15 different systems using Power7 processors. Not to mention the Xbox 360, Playstation 3, Wii, and not-even-out-yet Wii U that are all POWER based systems.