It's not unreasonable to expect that an airport with e.g. twice as many passengers as DUB may have longer distances to walk
Wait till they eventually get the Metro built.
The very original concept was that the station for the rail link would be in the basement of T1. At some stage that idea went out of the window, and then they built T2. Now, the plan is that the Metro station will be "close" to the Great Southern Hotel, which is about as far away from the terminals as they could put it without going outside of the major roads that circle the airport. From Pier D to T1 is bad enough, the extra distance to the Metro will at least double the distance. That is not an issue for a resonable number of people, but consider the significant number of disabled, very young and elderly people that for good reasons are not able to walk long distances that will probably include steep slopes, if the present scenario is anything to go by. In theory, there will probably be travelators, which is fine when they work, and a total pain when they don't. Denver has an underground link from the main check in area to the remote piers that in total covers less distance with 4 stops than the distance people will have to walk at Dublin.