This is a stretch of the main street of Kinvara, where both of Johnny's parents were born & emigrated from, meeting in New York. Since everyone in Ireland has relatives in America, it might not seem like any big deal. Johnny certainly isn't interested in his roots, & I don't get the impression that people here are all that interested either that I'm a daughter-in-law of Galway.
It occurs to me that given the popularity of Ancestry,com & 23&Me, maybe the fascination with royalty is that aristocrats are people who don't need to do their DNA to find out where & who they come from. They have what many people want: a history.