Why is this becoming normal?

As some of you may noticed there have been an influx of tank ekkos and all that lovely crap. I have seen everything from tank akali mid to tank riven and, in every game, they all manage to outdmg the supposed "dmg dealers" like yasuo. Why is this even a thing? Riot please do something about this. If someone were to go tank, they shouldnt be dealing as much dmg as someone who built full damage. This playstyle is really getting out of hand and hopefully you can fix it riot.