Seven years ago, struggling artist Thomas Kinkade sat in a secluded gallery well past closing time, determinedly propounding the virtues of his luminescent garden-and-cottage scenes to a young couple. He was going to give it a few more months, Kinkade told the couple, and if he couldn't sell enough paintings to earn a living, well, he'd close up shop and move on.
Today the shop is not only open, it is one of more than 200 Kinkade galleries nationwide. Media Arts Group, the artist's publicly traded company, based in San Jose, Calif., recorded $126 million in sales last year. Kinkade,...