I'd suggest that it's just too much. all the podcasts I listen to have a hard time justifying getting to Botcon if it's not within 3 or 4 hours drive, there are obviously exceptions but for them, $500 is large percentage of the money spent getting to and attending the convention, for us, it's less than half of our plane ticket so it doesn't feel like quite so much.

If I was attending Botcon this year I'd definitely be considering it.