It's my impression that opening up the dealers halls to the public is intended to help achieve 4 goals:
Increase York attendance to help pay for the show
Increase York attendance to help the selling dealers make more sales
Increase York attendance to help the manufacturers/importers reach a wider audience
Increase TCA membership.
Keeping the member halls closed to the public is likely to still be required by the PA Tax department in order for them to remain tax free. And it provides some incentive for joining the TCA.
Sorry, but you cannot please everybody.