The irony is, we'd have sold a 60k in the immediate by increasing season tickets.
For me, the killer is the digital tickets, and 1 paid membership (seasonal too, not annual) = 1 ticket.
It means the game is 'sold out', but there's gaps as people can't readily transfer tickets. When that happens a few times, people will reassess their season ticket. It's happened elsewhere for years - like at Man City;
There's people who go the game, who have no idea how to transfer their ticket to someone else. Nor do they know yet, that if they want to, that person would need to buy a membership to receive the ticket.
In a few years, if we have a decade like the last - with the current system, I think we'd struggle to sell the season tickets we currently have once new stadium novelty wears off, and fatigue/frustration of digital ticket kicks in.