I think that’s an interesting theory, but it doesn’t sound right to me. The MS stores sell products from those same PC vendors, and I’m sure that will continue. I think that Surface is more about making sure that the initial launch of Windows RT was running on some innovative hardware that will get good press. Also, it will set a quality bar so the 3rd-party vendors will have a reasonable baseline and won’t be tempted to ship low-end junk.
One of the problems that Microsoft has historically struggled with, is that people form their opinions on the whole platform, not just the OS. If someone goes to BestBuy and picks up some junky PC that is unstable or underpowered, it’s going to be Windows that gets the blame, not the PC. Intel has tried to fix this problem by providing integrated chipsets, recommended configurations, and even reference platforms - but it hasn’t worked. Apple doesn’t have that issue, as they control the hardware and the OS.
If that’s the strategy, it definitely has some risk. Microsoft has always emphasized its strong partner/vendor ties, and that it doesn’t (as a general rule) compete with them. There’s definitely a chance of alienating them with this approach. I guess less so now that all the other OS vendors are also hardware competitors (Google/Android with their purchase of the Motorola Droid, and of course Apple).
Apple buys their stuff from the usual suspects. But they're better at hammering on them than the other players. And doing themselves what their vendors are not up to.
Witness the new MacBook Pro with the Retina Display. Given a 2880x1800 display resolution, how do we display it on a normal 1440x900 15" laptop and realize the superior sharpness without screwing up all the existing software? Very cool! I hope it's not the last of the Jobs product pipeline.