where is the tank love?

First of all lets clarify my meaning of tank. A true tank is anyone that builds 4/5 defense items on a regular basis. Characters like Aatrox, darius, warwick, xin, Jarvan, shyvana, and the plethora of other false tanks that can build pure damage and out-tank tanks don't count.

why does AD and AP scale so well while tanks are left in the dust? I can't tell how many times I build pure tank for the team and completely get raped by the very people I have built my items to counter. Damage dealers can easily hit the true damage mark against tanks. what good is 4k hit points when a damage dealer can easily hit you for 1k damage, and have 2 to 3 attacks/sec and lifesteal at an astonishing rate while hitting you. It only gets more ridiculous when you count the number of champions that can deal true damage even without items. Why have tanks been left in the dust while Riot "fixes" the champions who didn't need fixed. Riot keeps fixing champions by upping their damage instead of evening the playing field. A pure tank vs pure damage should be an even fight and come down to skill, instead the scales always lean toward damage dealers. If riot wants us to just be glass cannons then bring back urf and leave it at that, the normal games should be at least fair for those that get stuck, or even like to play the true tank characters.