why are tank items not so gold efficient this seasons?

dead mans plate, sunfire cape sitting at 80% gold efficiency. because they both got their prices increased in the past few months. and dead mans lost 100 health and 5 armor way back. while sunfire did gain 5 armor I think it used to cost 2500-2600 now its and DMP are both 2900.

thornmail has 85% gold efficiency. I don't know about ibg. because the wiki doesn't say it but its in the 80% efficiency range as well.

the only one that is gold efficient right now is probably randuins. I mean the base stats are not but if you think about the damage reduction it probably makes up for it.

i know dead mans and sunfire both have passives. but am talking about the base stats here. many if not most items in the game are gold efficient without their passives or somewhere in the 90%+ efficiency.

I don't like the 2900 tag on these items.

if i had to guess its because non tanks like ekko and fizz synergize to well with them