I actually agree 100% on this losing the gold income after final upgrade is just not fair to supports, we just stop getting gold at that point in the game. And if you are good with your pokes could easilly do that by the 10 min mark so you are losing a LOT of gold through this.
Aditionally, I also didn't tend to upgrade more than once unless I had a full build. It simply wasn't worth upgrading to t3 for 15 spell power and 200 hp.
So for 850 gold, I used to get 20ap, 10% CDR, 50% mana regen, and a bonus 18 damage on my pokes (that was very valuable to a poke support)
now for 400 gold I get 60ap and 150 hp.
Those stats are SIGNIFICANTLY worse that even the first upgrade of the old item, the item itself is simply weaker than the old version AND it gives far less gold. AND it can potentially punish you for clearing minion waves.
so I'm definitly NOT 'saving 1400 gold' because I now need to spend more gold to get the mana regen and the CDR back and I simply can't get the bonus 18 poke damage back.