Why do you presume just a handful of customers?
Why would there be otherwise? As I said before without an established network there is no incentive for the company to accept my business and no incentive for me to give my business to them. There are less expensive options open to me and less costly customers for them in the states where they currently do business.
This is not just assumptions on my part. Several states have already passed laws allowing their people to buy out of state. None of the experiments were successful.