Are "Pure" Tanks obsolete?

A nice video on the matter by Stonewall. I'd like to add my own insight to it:

It's not just the tanks that are obsolete. The whole champion roster has shifted from utility to damage. The power creep in LoL is subtle, but it's there. Notice the changes:

• Spells with long crowd control effects are being gradually removed from the game
• Targeted hard CC (Rammus, Fiddlesticks) has been greatly reduced (to be fair, it was justified, as it was a point-and-click CC with no counterplay)
• Sejuani's slow on E has been reduced from 3 seconds (release) to 1.5 (second rework)
• The only immobilizes left that last 3 seconds or longer are Morgana's Dark Binding (highly frustrating for many people) and fully charged Ashe's Enchanted Crystal Arrow (if you got hit it from that distance, you deserved it)
• Hard CC (Stun, Taunt, Fear - arguably Snare/Root as well) is more and more sparse in the new champion releases
• There are only 3 champions with Taunt, all released 5 years ago
• The last released champion with Silence was ~~~Talon~~ ~~ŁeBlanc~~~...oh, wait. Malzahar. 5 years old as well.
• Displacements are the new trend (Knockup, Knockback)
• Since the beginning of 2012, 34 champions have been released (from Sejuani to Rek'Sai, counting Sion as a new champion). 24 of them have displacements in their kit. That's 70% of them with a knockup or a knockback.
• Only 21 of the older 90 champions have displacement spells (and that's counting Anivia's and Trundle's abilities as displacements). That's 23% of them.
• This slowly reduces importance of Tenacity, key point of the Defense mastery tree and important tank items (Mercury Treads, Juggernaut).
• Knockbacks severely hurt melee champions, especially initiators.
• Supports were shifted from utility to damage
• The whole trend started somewhere after the release of Leona and the emergence of "kill lanes". Kill lanes were a direct counter to "traditional" supports - Soraka and Sona
• The answer to "kill lanes" was ranged harass, and the term "disengage" surfaced - next two released supports were Lulu and Zyra, and champions like Janna and Morgana became appreciated. Harass lanes were losing to sustain lanes, though
• Overall a rock-paper-scissors game of kill-harass-sustain became a staple of the bottom lane
• This whole system went to shit with the release of Thresh, who simply did everything other supports could do, topping it with one thing no other champion could (Dark Passage).
• With season 4 and the changes to support items, all supports gained AP scalings on their utility, and by that I mean they lost base values on their spells, and now they have to buy AP to compensate
• Annie and Fiddlesticks were already considered situational supports, and so the AP support meta came to life, giving some spotlight to Zilean and Karma
• % health damage EVERYWHERE
• Blade of the Ruined King is the biggest culprit here. The simple fact that the anti-health item is considered core on many champions even if their enemies buy no health items whatsoever makes it absolutely broken. Do you see mages without DoTs buying Liandry's Torment? Meanwhile, bruisers, fighters, assassins (!) and carries are all buying BotRK - for some it's "just-one-dmg-item-then-tanky", others want the invaluable active. This indirectly weakens items like Warmog's Armor before they can even be assembled. Anti-health items should be a response to health stacking, not core of the build
• Every other new release (Jinx, Vel'Koz, Gnar, Kalista) contains damage scaling with target's health
• Numerous champion reworks (Shyvana, Maokai, Gragas, Sejuani) gave them damage scaling with % of target's health. This brought them to "viability", but left their worse-damaging brethren (like Shen and Nautilus) behind.

Overall, it's all about damage now. Tanks (or: bruisers, who took their job) are now supposed to deal damage instead of providing disruption. Supports are all starting will AP item (in competitive) and some are buying Mejai's Soulstealer. Everybody deals damage now. Is this good for the game? Yes and no.

Yes, it solves people's problem with solo queue mentality. In season 2 and 3, some trolls used to pick full AP Nidalee as "support" and then proceed to get fed or feed, with no middle ground. Nowadays such attitude is quite rare compared to that period - supports have gold and deal damage now, and support players feel better about their role. If you deal damage, you immediately feel satisfied.

No, it's not really good in the long term. It's a power creep of a different sort. When every role is about dealing damage, it dumbs the game down. Tanks are not the only declining group, the other one is "true support" role (Soraka, Sona). The only true support left in LCS and popular in solo queue is Thresh, but that guy is just broken - his overloaded kit, without any scaling on utility whatsoever, is what all supports should be in the first place. If we lose tanks and true supports, the game will lose a layer of tactical depth of buffs, debuffs and disruption, and turn into a giant brawl of damage.

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If you wish to get more insight into tank itemization and apparent problems with it, feel free to check out my wall of text with suggested rebalance to all tank and damage items (just buffing tank items is not the solution, Last Whisper and BotRK need to change).