Why are we pretending only haki or only DFs are now supreme?
Yes, excessive haki can nullify effects of some Devil Fruits. But if, for example, Akainu's magma lands on you, that shit will burn you no matter the haki. You will be able to touch Akainu's real body, but the thing he produces is still hot molten rock.
It's about combining the two where the superiority lies. If you're a DF user it does not mean you lose against a haki master. You still have your own haki + your devil fruit.
Just look at Luffy's final attack against Kaido. It's a giant fist, clearly a product of his DF. But he also used haki. A regular sized fist wouldn't have done the job.
Immediately jumping to "oh, well as long as you have adv haki any devil fruit user is just fodder" is dishonest imo.