It's all in the chase.
So this guy has liked you for 3 years, but you got on well but weren't interested at that point, 2 years later you were, let it be known and so, for 1 year, you have both entered into a long distance relationship but only via Skype and phone, haven't seen each other.
He stated you two couldn't be "girlfriend and boyfriend" persay, or more until one or the other moved closer or in the same State.
A year later he's distant.. says he is busy.
If he can not give you a straight answer knowing that you are worried about why he is being distant, then why waste your time? A relationship at the best is hard, let alone long distance.
Honestly, Skype can be a good thing but also a bad thing and I'll leave that with you
I would say that it's become too hard, he's lost that "chase" interest as he has you and you don't stand your ground rather, ask, he answers and you leave it at that.. No chase anymore.
Be assertive, you are worth something and if he can't pull his finger out and realise what he has, let him go, 1 year is enough time to waste when you could be properly dating, going out to dinner, holding someone...