I have so many games where 4 of my teammates think a game is lost when they're just a little less fed than the enemy team. They have no comprehension of what a "comeback" is. I'm forced out of the game when I'm doing p ok.
That one person who thinks they have a fighting chance in an unwinnable game, is usually the person that belongs in their current elo.
Not everyone wants to play a 45 minute long 20% chance comeback every time they queue, though.
Ive actually been in quite a few situations where we would have won if we didn't /ff. Like we ace them, get baron, then ff........
comeback NEVER happen if teamates are giving up. if all 5 players are trying, comeback happen quite often.
but no, if we disable ff people will just stay in base
they just need to move around from time to time to avoid riot realising they arent playing.
so if we disable it you will just see a 
in the amount of afk and inting in lower elo.
I believe there should be several conditions to the FF. Along with time the EXP difference and the gold difference and maybe factor in the difference in secured objections. Not by ridiculous amounts of gold or exp. The purpose being when a tilted ally that feels no hope for winning sees the difference isn't that big (by surrender not being available at the earliest time yet) maybe it can un-tilt them so to speak. Just implement as a sort of morale booster.
