How does Dynamic Queue Promote Synergy

So Riot has decided to scrap solo q and ranked 5's in favor of you 5 man queuing in dynamic queue to support you building synergy with your friends.

This sounds all well and good. I can premade with 4 of my friends, and maybe we're good enough to get dyna-boosted to diamond. Great, we're at the part of the ladder where things like team synergy actually make a difference. With all this built up synergy maybe we can get to masters!

Oh but wait, now we can no longer queue as 5 and are forced to queue as a max of 3.

How the hell is this meant to promote synergy when the only part of the ladder that can't play as 5 is the only part of the ladder where synergy matters.

This backward way of thinking makes me think that Riot has put absolutely no effort into their decision making at all and that the only reason this decision has been made is because they do not want to admit they fucked up after months of scrutiny from the community. It just makes absolutely zero sense to me and I'm completely dumbfounded.