The issue will never go away. Any person can buy a membership and apply for tickets. There were thousands of unsold tickets by the time it got down to members for last night's game. When I checked last week after the all season ticket holders window had passed, there were blocks with hundreds left in them, all over.
It will only get worse, and the only way it will stop is if Season Ticket holders start attending.
Unfortunately, the only way that's going to happen is if a) they reduce prices drastically or b) they include all Champions League games in your Season Ticket price and make it compulsory. But I cant see either of those options happening anytime soon.