Tbh it was already highly likely ever since Luffy managed to defeat Kaido with nika powers. And considering shounen logic, there is no way that Luffy won't grow massively stronger from now on. Shanks and BB are his next opponent. They can't be weaker than Kaido, it would be illogical.
And now, Shanks one shotted an opponent who's 1/2 part of the force which defeated Big Mom who was comparable to Kaido.
HOWEVER, I still think the gap between Kaido and Shanks is close but imo Shanks definitely has the edge here. It's rather Big Mom who suffers from this chapter even more. At least Kaido also has some potential techniques like Ragnarok, his strongest TB or other higher end techniques to KO Kidd just like that, not to mention Blazing Bagua. But Big Mom? She spammed her entire skillset and still couldn't even KO Kidd for once...
If Big Mom is still alive, I hope she finds a way to age younger again, so that she can still be strong again, like in her prime.