There isn't any one particular thing that has been holding the domestic supply back. It's the development of that supply system and getting some of the larger pollinators to accept the fact that there could be a domestic supply.
It's being done, particularly in the province of Saskatchewan. Saskatchewan is probably the province closest to self-sufficiency when it comes to a large number of colonies.
That being said, the domestic supply could be part of the answer. It will never be the whole answer, but it could be developed into a larger piece of the pie.