This is just my viewpoint. No links or such.
When I lived in California working as a landscaper with my ex, one of our clients was a very highly respected CPA.
Before Eddie DeBartolo bought the team, the team was owned by Victor Morabito. In 1963 at age 45, he died suddenly of a heart attack. His wife Jane took control of the team until 1977. Our client was the head CPA of the 49ers during Jane Morabito's ownership. Jane went to Andy (Name not changed, that was his name) to ask how they could generate more revenue for the team. The first thing he suggested was to make suite owners pay for game tickets for the seats in the suites. He was met with resistance obviously, but the suite owners agreed, and this quickly spread throughout the league. So in a way, that could have been the pre-curser for PSLs. If suite owners had to pay for seats to view the games in the suites they rented from the team, then season ticket holders should pay for the right to purchase their seats.