I mean, the pathway and delivery could 100% be new, but the treatment doesn't have to be actually new.Modern science can do many things that natural cures cannot. Re-attaching severed limbs. Open body surgery without dying of infection. Etc.
Let's weigh the evidence for & against an unknown natural treatment (that is worth using):
One one side, the last 10,000 years of human civilization has not been able to find anything. And on the other side, with the benefit of modern research, there is . . . zip. Nothing been found. There still isn't even any evidence to suggest it might exist.
One could say "it's impossible to prove a negative" but IMO the case for the negative is pretty strong here.
I absolutely do believe mankind will invent a better treatment in the next few decades. But it's gonna require something that was not available to mankind until recently.