Are shifting demographics killing sales of veteran artists at cons?

Last week Denise Dorman, wife of veteran artist Dave Dorman, who is best known for his excellent painted covers, wrote a post on her blogm which is called Comic Book Wife. The post was titled: The Hidden TRUTH About Comic Book Convention Earnings: For Creators, Have Comic Book Conventions JUMPED THE SHARK? in which she pointed out that sales for her husband were off at several shows this year, and given the costs of exhibiting—hotels booths, food, travel—it made more sense to stay at home and do actual money making work.