It's also one thing for friends to make an impulsive offer out of love, and then to find out the time and distance involved and think about their own lives and time constraints- yes, they are being "selfish", but maybe they, too, are taking care of themselves. Yes, they shouldn'ta offered in the first place, but I bet they don't have any idea how it let you down.

Oh, I'm just trying to put a pretty light on it- of course you're disappointed! I wish I could drive you- we'd have fun in the car!