Hey, a lot of us play ragtime on piano; some of us refuse to play anything else, and many continue to compose some truly wonderful rags, as in Galen Wilkes, Tom Brier, Hal Isbitz (sp?), Frank French. Several actually make a living (albiet a frugal one) playing and recording ragtime, as in Max Morath, Richard Zimmerman, Mimi Blais, Scott Kirby, Sue Keller, and the granddaddy of 'em all, Ragtime Bob Darch. We even have annual festivals all over the country where you can get inspired by the very best players and dance to the many ragtime orchestras. Recommend you head for the West Coast Ragtime Society's web site and check out the ragtime calendar of events, plus the festival, midi, where to buy ragtime products, etc. links. Next big festival is coming up June 7-10, the umpteenth annual Scott Joplin Festival in Sedalia, MO.

As for why pianists don't play ragtime? My guess is that most folks haven't a clue what ragtime is. Soon as they hear good ragtime, most pianists I know get infected really fast.