[2020] (PBE) Why aren't fully upgraded Support Items considered Legendary?

Support Mythics are already incredibly lackluster. Why make it worse by having one of our items not even give the bonus stats from it? The new control ward bag is considered Legendary though, even though it serves the same purpose.

Furthermore, Boots don't count towards the Bonus stats either so Supports get at max 3 Legendary items for their mythic bonus when fully built. A whole +6 to the Armor/MR aura of Locket, 9% movespeed or 15 haste.

I really hope this is just an oversight. Also, I did only get to check this with Shard of True Ice because every other game the enemy team just dc'd because they weren't winning the early game but I doubt the other items are different.