The market is moving to mobile devices driven by vendors who don't give a proverbial about NET, or about SQL Server for that matter. Would you mind qualifying this rather general statement of "the market is moving to mobile devices..."?
While certainly not a false assertion, surely you'd concur that the market is moving in many directions that are independent, and really neither congruent nor incongruent.
The most deployed database in the world is sqlite which is an absolutely dominant force by now and IMHO you'd be a fool to consider anything else for a mobile app at this stage unless you're using cloud in which case you go with the provider who offers the best terms. You do realize, I hope that sqlite is viewed by even its supporters as "hacky" and still quite immature as a product....