I think some users are pushing the panic button before they need to, here. There is nothing to suggest MS is backing away from WP. Actually, every statement tells me they realize how important mobile is to the future of this company and their products. All I keep hearing as far as gossip from Mary Jo Foley and Mr. Thurrott is that WP 9.0 will be the long sought unification of mobile apps and mobile OS from WinRT and WP.
Besides, let's not forget what company we are talking about here. Microsoft is not a mobile only, or even mobile dependant, company. It is a vast, enterprise driven company with fingers in all sorts of profit producing pies. This is about the future, and MS fights for that. They do not need to be #1 in mobile phone OS's for this to be worth them to keep it up. They will release things on Apple and Android, and will continue to have desktop (which is declining but nowhere near dead, most likely not even really dying) software income, they have Bing turning a profit finally, they have XBOX entertainment services either established or launching producing profit, and maybe half a dozen other money making products I am either forgetting about or have no idea they are involved in. If WP continues to grow at .5%-1.0% a year, the money keeps getting better, they have their own OS to sell and improve on. That will be enough to keep them in the game, nibbling at Android and Apple. As more and more people use live tile based OS, more and more they will see WP as something common.
No crystal ball here, but I say through 2015, or even 2016 is assured. Any other worries are just a tad premature.