Support items are crippling.
Just watched a lux support without the support item. Sure the early game was weaker, but thanks to the Doran Ring she could keep up the harassment and push our side out of lane. Eventually it came round to her sniping kills and racking up gold. I reckon most mages could pull this off too, whenever their adc would leave lane to get items they'd take the next wave and a half worth of gold.
End game, where we had about 5-6 completed items, my side slightly in the lead and 1 dragon off of the soul, Lux damage output without getting a gold generating item was stupid, top lane shen was also out tanking a Leona support thanks to the support item she got stuck with.
30 AP/AD and 300 health fucking sucks, the support dedicated THEIR TIME and THEIR INCOME to have an item they cannot upgrade with gold for a half item worth of stats. The support mage gets the advantage in the mid late stage of the game thanks to not bothering with getting the support item and the rest of the team made do with their single wards.