I agree it hasn't been a closed shop up to now but moving forward in the PL it is likely to become so, as there will be no opportunity for persons to gain enough points through the ballot to break into the 1500+ grouping. It will be a case of waiting to fill dead mens shoes, with younger supporters who want to start going to away games unable to break into that that grouping.
Also, while not quite systematic there can be no denying there has been an element of points preservation at the top end by persons either looking to sell on their tickets, or in the case of Millwall last year, and probably Plymouth this year of buying tickets and not even attending.
Ultimately the club is in a no win situation though, as there is no obvious way of pleasing everyone, and the current situation is about as fair as they can get it I guess, even though I would like those that take up tickets with no intention of attending penalised in some way or other.