Here is the problem with support: if you tweak anything in a way in which a non-support player can even marginally capitalize on the change then it will not happen.
That is the problem. If support items began to be more cost-effective AND do more damage then non-supports will build it.
If casting wards granted XP, non-supports would build sightstone and drop a bunch of wards at the base.
If gold income items granted more gold, non-supports will build them.
That is the central issue with any change that riot makes to that position: if any NON-support player can extract a benefit from it then the change will not go through.
I do think the clearing of wards granting xp was a great change, because the jungler and the support are the ones that clear wards typically. The XP is enough early on to make a little bit of difference for a support, but not high enough as the game progresses for other positions to capitalize on the extra xp.
When I jungled I sometime leveled up off clearing a ward, but the XP was so low that I was probably going to level up off doing a small monster at a camp.
This item 
is already being built by non-supports in my games. The item is great! However, it is problematic now because others are beginning to build it at other positions.
It will probably be nerfed and this is unfortunate.
If they made is so that specific items could ONLY be built by someone who has at least one gold income item then that may limit this problem, but I feel like riot would have already made this change if it was that simple.
