What MS is aiming for with the Surface devices, is a decent number of sales that will keep it profitable and alive. But, mostly, MS has been designing and developing ideas via the Surface line that, hopefully, will lead the Windows OEMs to come out with a lot more desirable devices. Windows was not the problem with PCs. Microsoft was not the problem with PCs. The problem was that the OEMs were producing devices that could attract people to Windows.
When it comes to ‘dirt cheap’ devices, the real fact is that, even those cheap devices were and are very capable, and can do most of all of the same stuff that an Apple Mac can do. Most consumers don’t need the $2,000-$3,000 PC to do whatever they need to do. Apple stuff is about status and showing off and bragging. There really is no need for super-expensive PCs, or even expensive tablets or expensive smartphones. For what the vast majority of people do with their devices, a $150 smartphone will do, and a $300-$800 PC will do. When even the cheap stuff lasts as long as the expensive stuff, and can basically do the same stuff, then, the higher prices are about status and bragging rights and being cool.
I think Microsoft's objective with the Surface devices is not to create a profit center, but to set a benchmark.