I'm the other way around. I'd never dream of giving up riding. Every summer I think about selling my snowmobile, but I never even consider getting rid of the bike in winter. I think about what mods I could buy with the money from my sled.
I just don't use the sled that much. In a really good year(which we haven't had recently around here....mild winters and low snowfall) I might get 1500 miles on the sled, and have ~3 months at best to do it in (mid Dec through mid March). You have to carry the sled everywhere with something else. Constantly loading and unloading it from the truck. Gotta bundle up like a Stormtrooper to go for a ride without freezing your balls off. Aside from a couple good areas I know, trails for the most part suck, aren't always well marked, and you're limited to designated trails, you can't just ride anywhere. If you're not familiar with the area, prepare to get lost in a hurry. Signage is sparse at best and published maps are in most cases useless. Too many sleds and not enough groomers, espicially in high traffic areas like tug hill and old forge. By noon everyday the trails are absolutely destroyed, lucky if you can manage 30mph. The Colton/Long lake/Cranberry lake is one of the few areas where I can actually enjoy riding the sled. Plus snowmobiles tend to require a lot of routine maintenance items. Replacing carbides, replacing track hyfax, replacing the drivebelt, rebuilding clutches, rebuilding shocks, bearings don't last long, bushings don't last long, skis get beat up, ect. Most of those things have to be done every year, if not multiple times per year if you ride hard or race. Plus, it's tough to plan for a "snowmobile trip", since you're never sure if the weather is going to cooperate. Warm spell, snow is ruined. Need snow? Probably won't get any and trails will suck. I've had sledding nirvana a couple times.....20 degrees, perfect snow, very low traffic, wide, flat trails. Except for every "nirvana" ride, I've been on 10 that sucked ass. Hard, icy snow, sled's overheating constantly, trails that redefine "bumpy", crazy traffic. I've come back from a few thinking "f this s, I'm selling the damn thing.".
On the other hand, the Vmax can drive itself to where it needs to go, easily gets 8-9k miles a year, has virtually unlimited prefectly groomed "trails" to anywhere in the country (aka public streets). Maintenance amounts to oil changes and tire changes. Bearings, clutches, shocks, all last for 10s of thousands of miles in most cases. It's always easy to find low/no traffic roads. Public streets are well marked, even the back-back Adirondack roads have signs pointing which way to major towns, keep riding you'll eventually wind up somewhere. Never truly "lost", just not where I might have intended to be. I have one of the fastest sleds out there (Yamaha 1000.... modified R1 motor) and the Vmax still beats it for fun factor. Plus, you never get stuck on a motorcycle, at least street bike. I've never come back from a ride pissed off. A couple where I was 5 miles into a 100 mile commute and it started raining I wasn't exactly thrilled, but when I arrived soaked to the bone, bike covered in road grime, I was just glad to get home, not sore, cold, and exhausted from a 50 mile mogul fest, dodging ********* riding down the wrong side of the trail, and eating crappy food at exorbitant prices at the snowmobile "lodges" that cater to the crowds.
But I hold onto both, since otherwise I'd be bored all winter. A bad day of riding still beats a good day at work I suppose. But if I had to choose bike or sled, the sled would get sold in a heartbeat. Just isn't as fun, isn't practical, costs more to use. The sled is purely a toy, where the bike can at least pass as practical transportation. Just doesn't have the allure of adventure motorcycling has.