Nono, everyone here doesn't quite get it perfectly, but that has to do with OP being bad at describing what he means. I agree that 'The Meta' shouldn't be some immovable object that everyone must worship. I mean, I used to main solo mid Ashe back in the day.
But what OP is really intending to say is that in a game of 5 random people who have never seen each other before the 1 minute of picking champions, you rarely have time to devise a non-standard plan. Everyone knows that bruiser top/mage mid/AD+Support bot/Jungler works. It is solid and stable. The enemy might mix things up, but that set up can deal with almost everything.
And in turn, that it is often a better idea to follow that standard pattern than to try to spend that minute figuring out who is going where and playing what to take advantage of a double mage jungle with no smite that intends to only farm the enemy jungle. Or a no jungle tri-lane mid intent on pushing to inhib by 10 minutes.
The non-standard teams can work great, and you see them sometimes in tournaments as specialized strategies, and they work awesome. They are also very hard to pull off in a solo queue type situation. If you have a 5 man premade (Or random yourself an awesome solo queue group), breaking the meta can get you huge benefits. If you are in a game with 4 randoms, don't expect your double jungle to make the Kog that instalocked happy that he has to play without support against a Blitzcrank.