@SalmonGod:
The whole point of those early game teams is to get a very significant advantage early on in an attempt to win the game fast. If the other team can survive untill minute 40 (random number, actually depends on the teams), they have a chance of turning it around. It is often a bad habit to surrender at 20 just because your team is very late game and stands 5/18 or similiar, while you haven't lost third towers (sometimes not even second ones); the LCS and season 2 finale had several games that where ultimately won by the "loosing" team being able to stale the others long enough.
I for myself played several games which we initially lost hard (the most extrem one was something around 3/25 and only one third tower left at minute 25), but which we won in the end (sometimes due to much higher late game possibilities, and sometimes due to the enemies making a severe mistake).
There are rare cases where the start game is so totally lost that a comeback is impossible, but I think this is just a very minor percentage (except maybe in lower ELO, because without still getting enough farm [despite your enemies advantages; note that this does not mean you need to get equal or more farm than them], coming back is impossible). You also don't need xp over time, because situations where you cannot even leave your base anymore rarely occure that early, and often are your own teams fault by not warding enough.
Oh, and please don't start with that "I'm just voicing my opinion", because so do I. I never told you to shut up or tried to silence you in any way. I just gave you an advice, and I was, and still am, serious about that one: If you don't have fun with LoL (or some aspect of it) because majority does not agree with you, then just don't play it.