This is kind of the most important quote in the entire tank meta discussion, in my opinion.
There IS a benefit from tanks gearing to be tankier, to have huge hitpoint pools and high parry and stay in tank stance - but this benefit in current raid content is absolutely negligible. Tank healing is not difficult. In most cases it can be done by a regen and a fairy. Whilst people will argue that the dps-tank meta existed in 2.0, noone can possibly say with a straight face that it was as drastic as it was now.
Bahumut Prime, Nael and Twintania all hit incredibly hard, and consistantly, with heavy tankbusters coming at a rate where you barely had enough cooldowns. Spike damage was high. Raid AOE dps was still high but seemed to come in more separated bursts. Your tank dying to a tankbuster/auto combo was a real issue in a lot of these fights when done at the expected gear level or below. There were enrages and dps checks to hit, but they werent the primary reason for failing the fights. Tanks had a choice - maximise their own survivability and make the fight easier in that way, or try and maximise dps to help push phases at an expense of a riskier fight.
The current tank meta does not really have that choice. There is virtually no difference in the effective outcome of a fight between a tank that goes in in 190 gear and one that goes in in 210 gear, outside of higher dps that makes the enrages less taxing (and shortens the fights). The actual mechanics and tank survivability is such a minor impact that there's no tangible benefit to a tank being tankier.
THIS is the entire crux of why tanking feels weird to a lot of tanks. There's just no reason to be tankier. It makes such little difference due to how the fights are structured. You'll see more impact from your DPS PLAYERS getting a chunk more vitality naturally on their upgraded gear than your main tank getting higher health.