There is little real depth of talent in the rugby union ranks these days, which could be as an alternative source of players. As an example, Aspatria and Wigton both play in the North Lancs/Cumbria League these days, which is a long way below the level that both used to play at (National League Three and North One respectively).
Living across in the east of the county the local rugby union clubs largely have the same problem of retaining players beyond school level. The player pathways at school/junior club level are also well defined, which means that there are few hidden gems that have not already been picked up by Newcastle Falcons and Sale Sharks.