Google provides me with a service. In that respect I don't care how that service is provided and on what technology that is based. It could be a giga-cluster of retrofitted Commodore 64s thrown out in orbit to save on real estate costs, kept in place by a reinforced fiber back down to Google HQ. As long as the service works, I wouldn't care less.
This gives google complete freedom in their implementation, so they pretty much built up their own infrastructure from scratch, for a very specific purpose.
Microsoft on the other side delivers software, general purpose platforms which you can deploy and build your own solutions on. Granted, they got the whole internet thing a little late, but I can't blame them for trying to exploit the technology they already posses instead of ditching it all and starting from scratch.
With Microsoft's solutions, I know I can make them do whatever I want, on pretty much any x86 hardware, and I know it will work. "Google OS", for a lack of better name, I doubt would be particularly useful for the general public.
I don't think it's surprising for a platform tailored for one specific goal to perform better than general purpose platforms in that specific area, but that hardly means that the other platform is worthless.