Being elected president is not the time to learn a new technology suite. Hopefully most presidents have better things to do with their time than that.
At that level your people have people who have people to deal with that kind of minutiae.
At what level does this stop being a waste of time for the person?
I'm not suggesting Obama should have been forced to change, but every else in his administration was forced to change. There's some serious clashing between the need for secure devices and the reluctance to change from old technology.
My understanding is that internal hardware was removed/shielded, and I assume software modifications were made as well, like only connecting to specific cellular base stations (such as the one in his official vehicle).
Also, he DID swap out his phone for a secured one, and his staff instituted a number of security protocols to keep it secure.