It will depend on a few factors but I don't think it would be unlikely. I feel that if a numbered entry can be an MMO then it can be a handheld as well. Also, even if XVI has already started pre-production, that is still largely the concept stage as opposed to actually starting to code and translate concept sketches and character sheets into models, so it could be possible for SE to wait and see how XV does. I would also point out that Type-0 HD will probably be a factor as well as FFX HD. I think SE really is trying to gauge how profitable it is for them to focus on consoles. Then again, they did say they were creating a new studio focused on it and Tabata has stated in interviews he still feels the franchise should be on console so who really knows?