Microsoft will never reenter the Flight sim business, there's no money in it. There's been plenty of talk (not rumors either) of Microsoft focusing on its core business and releasing ventures that are mere distractions.
http://www.gamespot.com/articles/microsoft-ceo-candidate-may-consider-selling-xbox-killing-bing-report/1100-6416052/
As lucrative as the xbox franchise is, there's a possibility of that being released from the MS umbrella. Xbox has and always will be a more lucrative venture than flightsim ever was. The whole idea behind flight Sim was never really a smart business decision. For a company to make a platform and then allow everyone else to build on it and they make the money is not really a sound business model.
In my opinion, LR is making the same mistake Microsoft did. You cannot really build an organization without recurring revenue/repeat business; however, once you buy the software how does LR make any more money? The reality is that many simmers are not smart consumers. An example of that is they continue to invest money in a platform that is no longer being developed and believe that by that minor action some resurrection is going to occur.
The P3D franchises are doing things a bit different, they are targeting a specific market (the training market). Simulation training has proven to be a viable and cost-effective solution as opposed to real on the ground, in the air, and on the water exercises. Compared to the industry as a whole, most flight simmers at home are not training under some formal curriculum. We will never be a major consideration for P3D.
The only real options for the flight Sim entertainment market are XP and flight gear. As making money becomes more of an issue I would continue to keep an eye on the validity of XP (in my opinion).