B teams aren't progressive. Having colt sides who are artificially pegged back and prevented from reaching a higher level of football aren't doing anything for the game. Kids will learn far more playing with and against professionals in a competitive dressing room where teams are playing for promotion or relegation than they will playing for colt sides in a glorified reserve system.A mate of mine is a former player and one of their record goalscorers so used to look out for their scores.
Realistically though these clubs are just blocking the path of more progressive clubs and the likes of a Rangers B team playing competitive football.
Cup games featuring colt teams have been roundly rejected by fans of lower league clubs. Folk would rather stay away than watch their lower league side play Rangers or Celtic under 20s.