Wembley holds 90k, there are about 17k of Club Wembley tickets in the middle tier. They pay a fortune for the right to the tickets at all games but some do not take them up. There are on top of that, the tickets held back for the Football League and various sponsors. Leaves about 70k for...
I would suggest the vast majority of season ticket holders are individuals who don't share the ticket equally with friends or family, judging from those around where I sit. As others have said, what about those that can't afford a season ticket. They would be excluded from going.