The radius rule prohibits schoolboy players from joining schoolboy clubs located more than 49 kilometres from a player's school. The FAI are in favour of doubling the distance to 100 kilometres. It's perceived by schoolboy leagues near larger cities (and especially Dublin) that an increase in the distance allowed would result in the best players being poached by the bigger clubs.
This is bad for players, bad for clubs and bad for the Irish game in general. We know the impact of competition on raising standards in sport (and in business and other areas too where rivalry leads to innovation and progression). The prospect of a league, albeit in Dublin or Cork or Limerick and not in Louth, Kerry or Clare, that is competitive, with the best players at their respective ages, with coaching structures that are concentrated on those best players would result in better quality players feeding through to senior levels.
Of course, since roads have two directions there is nothing to stop, and a lot to encourage, a club outside a city from developing its coaching, linking with senior or professional clubs to attract players out of the cities. Competition works every way.