What with licencing fees and ATF compliance checks, not to mention inventory costs, I will be surprised if any dealers bother with BP much longer. My FFL told me recently that the ATF still does a 100% inspection of all inventory, sales records and invoices for BP and they all better match up perfectly.
The new wave of primitive hunters seem to use only BP substitutes in their in line muzzzle loaders, so there's no market there.
Fortunately, the several currently available BP substitutes, such as Hodgdon's Triple 7, work very well for most applications and closely duplicate real BP in every way except the stink.
It is, however, unfortunate that market forces and legislation are likely to eliminate the opportunity for shooters to freely choose between real BP and the substitutes.
Jack