Mobile phones are powerful enough to match PS2, maybe even the original Xbox in terms of power. Only problem is that touchscreens are a horrible control scheme, and no developer is going to spend millions of dollars to bring over modern games when the only way they would sell is free-to-play or for $5 max. Square Enix ports over older games, but most of them are over $10 and can't come close to matching the huge revenue that their F2P games have.
You're Gonna Carry That Weight.
Xbox One - PS4 - Wii U - PC