Not enough players & money to keep all the current clubs in business.
When clubs that are struggling for numbers and dont have any money to buy in players, then find themselves up against clubs with rich owners, then they get spanked week after week & lose even more players.
Sadly there are too many semi pro clubs struggling to survive, most end up going fully amateur and rebuilding but those with ambition just end up having to pay to compete & then go round the cycle again.