Nothing, really. Anything you got from the play store is just as capable as a foss file is. The only changes between open source and closed source are that open source runs the risk of virus clones being created, at the benefit of a person being able to review the code to check for viri.
I really don't get the debate against even just living longer...
The point of longevity isn't to have a rambling grape, it's to have people stay in their prime for significantly longer time. This means anything you could want to do then would be avaliable. With optimal mind too, imagine the spike in development of technology. Maybe the singularity or something, and all of a sudden anything anyone imagines can be done. It'll be a world of dreams, and surely dreams can't get boring, right?
Again, why can't we personalize our switches?