This article ( http://sports.espn.go.com/rpm/column...rry&id=3013994 ) seems to imply that it's more about safety than money.

"But one reason stands far above the rest for the classy Scotsman -- safety.

It's really that simple. Driving a Cup car, especially the Car of Tomorrow that will race in every event next season, is much safer than racing an Indy car on high-speed ovals.

Franchitti had two scary accidents in back-to-back races this year when his car got airborne and became a 200-mph target of destruction.

Sources say famous wife Ashley Judd had seen enough. She didn't want her hubby taking those kinds of risks any longer."

Can't say I blame him. And good luck to him. But FWIW, no, I won't be watching..