It is a barrier to investment in regions outside Dublin.
This is too limited a way of seeing it. The "barrier" for the regions would be much higher if Dublin Airport was inaccessible to them. It actually isn't a "barrier" at all.
That's probably understandable considering it's the only place in the country where transport issues will actually sway votes. However, with the parish pump nature of Irish politics, they have promoted the interests of their local area.
I'm mindful this is the Cork thread and we're veering onto other topics. However, those statements are simply bizarre given the political stranglehold that the Shannon lobby had over aviation policy for decades, and really only ended because of international developments.
Now, Shannon Airport was a good example of how a point of access could perversely become a barrier. Dublin Airport isn't really.