Even that is true neither the DAA nor the airlines would want every passenger to travel to/from Dublin airport on public transport. The DAA make millions from car parking charges and the airlines that bring the millions of passenger to/from the airport argue that because many of those passengers are spending money in DAA car parks that they should receive more favourable terms with the DAA in airport charges. This is why O'Leary was opposed from year dot to a rail link to Dublin airport as it might weaken their hand when negotiating airport charges.

In any case, the cap has already been breached and the problems that the cap was intended to protect us from does not exist due to infrastructure upgrades in the meantime so it serves little or no purpose anymore.