One of my close friends is moving to Madison, WI. Just 2 years ago, she moved back to Chicago from living out of state, and I was so excited. We could actually be friends again. But, in the past two years since her return, I saw her only once...on her wedding day.
3 years ago, another close friend moved back even closer to me. From Nebraska, to a Chicago suburb just two towns over (30 minutes away). I've seen her 3 times in those 3 years.
These are close friends. Well, at one time they were. But, if you don't live within a 10-mile radius, good friends become great acquaintances.
It's why we should all live in a giant house together.