Gonna say this again, especially now that multiple people seem to be focusing on it. Tank Items need an overhaul. They are extremely unsatisfactory to buy and with so many innate ways to ignore defense these days, hardly feel like they are making you any more durable. The only champions these days that feel durable these days are the ones with innate defensive mechanics that don't require them to have items to work, so why even build defensive items? The few defensive items built are hardly ever bought for the stats they provide and more for some insane active/passive effect they have, and, even worse, those active/passive effects are hardly ever defensive based. Some are, but those items are few and far in between and, even worse, often require you to build other defensive items to be worth it (like Locket and Gargoyle's).
Defensive items aren't used for defense anymore, just for really good passive/active effects that help your champion deal more damage (Sunfire, Deadman's, Abyssal), shield other allies (Locket, Knight's Vow), or some extremely strong synergy with your kit (Righteous Glory, Spirit Visage, Iceborn Gauntlet). OR they are situational and only work a fourth of the time (Randuin's, Thornmail, Adaptive Helm). Only two that are just pure self-defenses is Gargoyle's (as said, that requires you to invest into defensive items as a build which, as mentioned, isn't worth it) and Warmog's, which ALSO requires an investment in more health.