I can't say I admire his work, but it's wise to try to understand the appeal of any art SO popular...
There has to be something of real value that I've been overlooking. For me, his paintings felt saccharine and calculatedly gooey, as if they were painted in Fluffer-nutter: yet I wonder if that golden glow (note those windows, in daylight yet) wasn't exactly what his fans craved? It's intensely romantic, nostalgic, and, well, sweet.
An excerpt from a Thomas Kinkade painting, illustrating his golden glow. Believed fair use.
This POST at Lines and Colors.com calls Kinkade a "fantasy painter." The illustration of a Disney Tribute canvas certainly underlines that quality. Kinkade called himself, "The Painter of Light" - a moniker he has to share with Turner.
Maybe the secret of Kinkade's surprising success in the malls of America was that he was painting a nostalgic fantasy that deeply appealed to people who do not usually buy much art? Whatever the quality of the art, you have to root, just a little, for any artist who can sell paintings like hot cakes... bathed in golden syrup.