I think that realistically speaking it will be a long, LONG time before there's a miracle drug that could theoretically stop male pattern baldness + reverse it entirely, which is what I assume you mean by "cure". What's more likely to happen in my opinion is that someone will come up with an alternative to finasteride/dutasteride that stops male pattern baldness in its tracks but without messing with your hormone levels (to avoid all of the potential side effects of inhibiting DHT). This is still effectively a cure, but it's preventative. Think of it as a vaccine of sorts. If you're already bald, odds are that your only options going forward are going to be along the lines of things like Minoxidil, transplants, and the cloning of follicles from stem cells.
I just don't see a miracle drug both stopping and regrowing hair that's long gone anytime soon with our current medical limitations. Maybe I'm wrong though. Hopefully I am. In the event such a drug finds its way to the market, I would imagine treatments like finasteride would become obsolete.