Non Support Champions Feel More Helpful Botlane

It could just be the elo i'm in or other people and adc's can feel it as well. Whenever I play botlane I constantly find that mid laners top laners and junglers support me better than actual support champions. Brand vs Nami for example. He provides cc just like Nami can and poke for so much more damage. Sure Nami can heal but that wastes a lot of her mana and he can out damage her heal. Brand can be just as if not more impactful than she can in team fights. Why play Thresh we you can play Nautilus? He's much tankier and provides much more cc. Sure some support have really niche qualites that a non support couldnt hope to fullfil but most of them I feel like are outclassed by other mid top and junglers that go botlane to support.