Why can't we leave a game 5 minutes after having a DC?

Dunno if this has already been asked on the Boards, but then again i'm from EUW. I only came here because of higher chances of recieving feedback.

DOTA 2 and LoL have been targets of many comparisons. Most of which with the intention of knowing "which is better" Of course, they are different games with different mechanics and learning curve, and the choice between both must be made personaly

But that's not the point

There is one thing DOTA does much better. That is handling with negative behavior (that includes flaming, intentional feeding, and AFK'ing) I am not really into the "flaming" part, cause i've only played a few games of DOTA (mostly because my hardware can't handle it), but what i do know is that if someone AFK's in the game they have 5 minutes to reconnect. From there on out people are free to exit the game.

Why isn't this in League of Legends? Yes i agree that in DOTA you can end up with almost an hour of non finished games. But better have that than 20 minutes of waiting to surrender. And besides, implementing this measure WILL NOT increase the leaving rate of games, since the original AFK'ers will still get punished by the system

So the question still stands Why can't we leave a game 5 minutes after having a DC?