>>one application that runs on all platforms.
>All platforms?
>Ios?
>Mac?
>Android?
>Windows 7?
>Windows XP?
>In the platforms listed above I've accounted from most of the running platforms on the planet.
>Will that one app run on those platforms?

Somehow I have doubts on a "one size fits all" strategy.

The way I see things, what will sink Surface and Windows RT is a lack of an exclusive "killer app" -- something that is so compelling that people will get the platform to run it -- because it doesn't run on anything else. Microsoft wants to set up an ecosystem much like how Apple has with the iPod and iPad with iTunes. Problem is, there aren't any compelling Metro apps (yet -- and unfortunately the situation doesn't seem to be changing), and unfortunately Apple already has a "jump on them" -- as does the Android platform. What Microsoft really needs is something that is unique -- something that isn't already available, or as easy to obtain on any other platform. Basically, they need a niche -- just like how Apple found one when the Macintosh was introduced.