It's easier to keep in contact with people within close proximity - there's less effort involved in seeing them. But what happens when situations change? Most of the time you grow apart from each other; sometime's you may look back and think and think it's sad that you don't talk anymore when you used to be the closest of friends, the reason behind it is not just theirs alone but it's yours too. No matter who you know you have a relationship with in order for it to grow and keep growing it takes a mutual effort, if it's just one person reaching out to contact the other soon they will grow tired of trying and leave it all behind too.
it's a two way street