We back here in the colonies New England and all the rest,, still have an interest what goes on even though we declared our independence from Britain 1776(200+ years ago).
With a last name like Wiltshire I should be a bit more concerned about who's marrying who in the royal family but I don't really care, my wife is from India and so she naturally has an interest being that her country gained independence from Britain in 1947. I think because Britain has left it mark on the world: "Rule Britannia, Britiannia Rules The Waves".
So it easy for me to see why people care even though these Monarchs hold very little power now a days they represent a glorious past to which we were once connected.