When you are in a ranked team five v fives, you are obviously using a microphone to communicate with eachother. You are also given a week to prepare for your game. This allows you to do unique stratagies to help you win the game that you don't get the oppurtunity to do in solo q. As for why lane swaps happen it has a long history in why people do it.
When the game first started people did normal lane phase in tornamants, but than people began to develop unique strats like "four man dive the top laner level 2" or "all man invade the jungler level 1", as people perfected these stratagies it became very clear that for both the top laner and the jungler it was very dangerous to do normal lane phase level one. So than we had the strat of "duo jungle clearing"
Where the top laner partners up with the jungler, does a full clear, and boom neither die and they go back to a normal lane phase. However than people found a way to beat that strat, and so new strats were clearly needed.
So after the top laner and junglers were constantly being four man invaded on and dieing, it became clear the safest stratagy to avoid this problem was if the whole team worked together to remain safe in the first few levels by focusing on towers. Their are ways to negate this stratagy as well for example five man invade and use wards to find out where everybody is going. However at the current moment, the four man lane swap, trade towers is the safest way to play the game in the early levels to avoid casualties.
