Who says they can't co-exist? If anything, it looks to me that it's traditional handhelds that are in the most danger of getting overtaken by phones and tablets. Cellphones have been booming for a while now and somehow landlines still exist.
"Dr. Tenma, according to you, lives are equal. That's why I live today. But you must have realised it by now...the only thing people are equal in is death"---Johann Liebert (MONSTER)
"WAR is a racket. It always has been.
It is possibly the oldest, easily the most profitable, surely the most vicious. It is the only one international in scope. It is the only one in which the profits are reckoned in dollars and the losses in lives"---Maj. Gen. Smedley Butler