Im convinced that low skilled/elo supports roaming is one of the worst decisions they can possibly make. CMV
Start off by saying theres sooo many variables that go into the calculation. Map state, champ kits, vision, etc. First and biggest problem. If the opponent support stays you almost always have to give up cs/turret health. So right off the bat even if supp has success helping the mid laner or for some god forsaken reason they roamed top, how much advantage to the team is really gained? 450 gold max (unless bounty) to the team for the laner and supp (who doesnt need gold). Some gold from turret plating and minions. But then also, if you have a terrible adc the bot lane might get 450 gold as well from 2v1ing and turret platings and minions. It's really hard to calculate how much of an advantage is really gained from a successful roam in low elo. If a 2v1 bot kill does happen on your lonesome adc you may have just tilted them. Does that bring an advantage to them team? Probably not. And of course the worst case scenario and most common. The support doesnt help with anything and the opposing bot lane denies cs/gets a kill/gold from platings and cs/turret health. Seems like most situations end up with equalized advantages or a loss of advantage.