Surely the club would have a record of payment, if you miss a payment you cant use the ticket until the debt is recovered? Or something along those lines maybe.
Correct in theory, but how would you operate that at the turnstiles ? - Chaos would ensue
The whole point of the reduced prices is the early receipt of cash. If you then spread the reduced price over the season it's the same as a match day arrangement, and the club loses out.
There would be lots of time spent on working out how to beat the system.