I'd like to raise some awareness. And ask for some kind of statistic.
Supports after the shutdown gold changes which were aimed to increase single player agency has hurt supports the most.
Not all supports however, but those which cannot effectively roam or provide global pressure [ 
, 
- examples] as opposed to those that have great synergy and gank potential [ 
to an extent] .
So supports play in 1 or 2 ways:
-
They sit with their lane partner and provide as much assistance as possible to get through the laning phase in an even-positive way.
-
They sit the bare minimum with their partner and try to make opportunities on the map, mostly mid lane/jungle.
[Soraka is somewhat of a weird case in this with her ult allowing her to be of help even when not leaving the lane, similar to old Janna,TF with their passives]
What ends up happening is the following:
**The roaming support ** is at an advantage after their kit opens up [lvl 6] as every second they're not in lane, can be considered "global pressure" to the enemy, which in turn increases the penalty if a mistake occurs [mid laner (Cassiopeia) running forward to CS a cannon > gets charmed by rakan and dies 1v2] or provide that "passive threat" where the laner (Cassiopeia) has to give up her lead or sacrifice more in order to avoid that penalty which could result in a ; 1-2 Minion waves, Tower, Shutdown/Kill gold.
The only disadvantage to the** roaming support**(s) comes at the expense of his ADC which is a variable of those 2 kinds:
- Loses a bit of farm as farming in a 1v2 lane with most of the R-ADC roster is difficult.
- Ends up being punished severely after a mistake, getting killed and providing kill gold + losing 1-2 waves of minions.
The passive support most of the time, cannot afford to leave lane in order to provide assistance elsewhere, as their kit is not as powerful when open [lvl 6], and are prone to being countered by their role opponent or simply do not have the movement speed/kit to function outside of the "babysitting, E-Girl" style of play.
The advantages of the Passive Support are the increased pressure they have on their lane opponent when their counterpart is missing or a threat of a dive IF they are a highly aggressive support [like 
] that can take a tower shot or two. - this being somewhat avoidable when the appropriate lane opponent uses a long distance spell to clear the wave [Sivir Q, Cait Q] if possible.
Why did I mention the shutdown gold changes ?
Simple - Supports that do not/can not roam do not have access to the extra gold in order to power up in the early-mid game and in a sense get snowballed the most, as their opponents become gold starved and cannot afford Wards / Equipment.
Would also like to add the following "statement" - If the winning team's support is 1.0 of a player, then the losing one is at best 0.65 and at worst 0.30 of a player, that's how big the gap between the 2 could be in a single game.
TL;DR. The winning support in most games is the "roamer" as he is a global threat and can snowball out of proportion, the problem however isn't as much as the snowball itself, but the lead he gets with it, most often cannot be compensated elsewhere by the other non-roaming support(s), as global objectives are the main source of income/power currently, where as previously, before the changes, they were a sizable chunk, but definitely not where the gold came.
TL:Dr#2 - Winning supports / supports on the winning team compared to the Losing supports / supports on the losing team have way too much resources in comparison, and the gap only increases as the game goes on, with no ways to really compensate / come back.
