Only you can make those decisions. Keep in mind that road salt can also be a problem for cars -- I paid over $4,000 some years ago for bodywork, mostly rust-related.
There are also advantages to having two winter vehicles. If you don't want to ride, you have the car. If the car won't start, or your driveway/street is unplowed, you have the bike. Bikes are limited in their ability to deal with deep snow; cars lack studs and are limited on ice. Traffic jams can make car commuting in the snow impractical in some areas. I like having options in winter.
Paul