Not much - if anything - to do with reserve teams being in the pyramid. After all, that only happens in Spain and Germany (used to in Holland, at least for the Cup, in the early 80s). It's more to do with the scale of the various teams. Barring financial meltdown at a particular club, there is a clear gap between teams like, say, Nantes, that are D1-standard clubs that could sustain themselves for 5-6 seasons in the top flight if they get a good coach and assemble a good squad, and the clubs where D3 is their natural level. In England, virtually the entire Championship and even a portion of D3 (e.g. Sheffield United) are D1 clubs in waiting. Check the stadium sizes. Most of the Championship clubs are in 25K+ stadia, whereas in Italy, Spain the D2 clubs are in stadia as small as 7k . In other countries, you're talking about 5-6 teams max that are capable of mounting a promotion challenge and sustaining themselves. Even in BL2 only half are at that level.