I agree with everything you said. I think it is really is individually dependent, and a prerequisite being a low norwood to start. For example, ElDuterino has been maintaining on CB but he never went much past NW2 to begin with. But if you're NW4+ then yes, you're going to need some sort of 5AR inhibition to maintain for the long haul. The reason that finasteride is still the main solution for most people is that we don't have a topical AA that can effectively compete with DHT.The problem with minoxidil is that there's no evidence that anyone with even moderately aggressive hair loss can maintain on it in the long term. In fact, there's evidence to the contrary. We have several studies on finasteride that examine maintenance in the majority of men taking it over the span of 10 years.
Effectively with minoxidil you're making the gamble that you haven't inherited anything beyond a NW4 and you have at most mildly aggressive hair loss.
There's also another problem with minoxidil in that we don't know how it functions. With finasteride, if a better treatment came along, it would more than likely be possible to switch to that treatment and maintain the hair you've gained on finasteride. I don't think the same thing can be said for minoxidil.
A last point to consider is that the long term (10 years) studies on finasteride clearly show that the earlier you start the drug, the better results you get.