I would agree with Rick and add that it is a challenge to overcome competitiors and complete ecosystems that already have critical mass and momentum. You have to leapfrag the competition and that is a monumental task in handsets.
I'm unfamiliar with the surface RT's hardware issues. I had absolutely zero interest in RT since it wasn't the full operating system so I wasn't following it. From what I understand, the only hardware issue with the Surface Pro is the short battery life.
MS can definitely use Nokia's hardware expertise. XBOX 360 had chronic thermal issues resulting in the notorious "red ring of death." And the Sufrace RT debacle is another example of Microsoft's hardware ineptitude.
Microsoft has very high perseverance.. They didnt build the first OS yet they have the most popular OS. They didnt build the first browser yet has the most used browser now. They were very late into gaming consoles, yet beat sony and nintendo and became the leader. Ofcourse that is not the case in Phones yet... but lets wait and see ..
Just because they're late to the game doesn't mean they can't pull it together! Admittedly, a cohesive eco system isn't the first thing that pops into mind when thinking of Microsoft, but the few times they've jumped into hardware they have done well. The Xbox, The Xbox 360, and even the surface have all been considered the best in their class by many.
If they can somehow wrangle the divisions together enough to make it actually feel like a vertical system, it could be very good. I suspect they've been thinking of doing this for quite some time as the metro interface is designed to be functional across the entire spectrum of hardware they use.