I guess it depends. Generally I'd say if you're "pro" it probably pays the mortgage/rent... meaning people or companies pay you to ride. Film companies are a dime a dozen these days since cameras are relatively cheap, and it seems the number of "pro" sponsored riders in wrapped sleds has sky-rocketed in recent years. I don't think many people are earning a living off of snowmobiling, probably just a handful. Even then I'm willing to bet a lot of them subsidize their income in the summer working construction or doing something else as well. Chris Brown is probably the only person in Whistler making a decent money off of snowmobiling, there are a lot of "athletes" up here, but I don't think many get paid to ride, just gear.
It's completely different from skiing or snowboarding, where sponsors actually pay their riders travel budget to help them film and go on expeditions for magazine articles. An entry level travel budget is ~$5,000 from a single sponsor, and someone at the top is making $50-60,000 a year retainer/contract from their outerwear sponsor or ski/board sponsor on top of travel which can be in the tens of thousands if theyre doing Heli skiing trips to AK. Then there are photo incentives where athletes get paid from sponsors for every photo they get in magazines, or covers.
Major eyewear, outerwear and ski companies also shell out large money to film companies for them to use their athletes. They pay a title sponsor fee, then a per athlete fee. Depends on the film company, and other things. (it's not unusual for film companies to charge an athletes sponsors a fee of $10,000 or more before travel fees for them to work with that particular athlete)
I haven't heard of anything like that existing in snowmobiling.