First of all, as the role says "tanks" aren't supposed to carry games (and by this, I mean teamfights obviously, their jobs is to CC enemies and taking damage for their allies). Now you have """""""""""""tanks""""""""" like Maokai / Ornn / Sion who can 100-0 squishies without counterplay (since most of their abilities are point and click CC). The perfect tank in game imo is Braum, others are basically assassins / bruisers who just build full tank, are called "tank" but still deal an insane amount of damage that you can't deal with them anymore