In freezing weather, rinsing the car off after you have driven it is not even practical. If you think your car will be none the worse for driving it in the snow, you are delusional. Salt is definitely a killer, but there are other hazards on a winterly road...
Cinders and gravel ding your paint and gives salt access to bare metal and, of course, there are the snowplows that throw the stuff at you!
Careless drivers who underestimate slippery conditions run into you.
Cold dense windy air throws other people's car doors at you in the parking lots.
Freezing weather makes seals brittle and crack upon movement that you would not experience at warmer temps.
Freezing and thawing water in the joints of your car cause damage as it expands and contracts. Roads up north are crappy for this reason. This same dynamic is working on your car as well.
Ice and snow has to be removed from your car before you can drive it, so you take a nice scraper to your windshield and it gouges your glass. Snow brushes scratch and dull your finish.
Snow hides road hazards like pot holes, and sometimes even the edge of the road. Covered up lines in the road are left to interpretation; yours and everyone else's.
Don't get me wrong, driving in the snow is great fun. I grew up in Ohio's snow belt, and I used to do donuts with my old muscle cars. Those cars are long gone now. Only the guys that put them away for the winter still own theirs.
Back then I never thought winter driving was that big a deal, but a few years down the road you find out your car has rust cancer and it is terminal. It is true that your 911 cost about as much as a used minivan. But if you are going to treat your 911 like a disposable minivan then that is what it will be... disposable As the number of older 911's on the road grow smaller and smaller they will become more valuable, unlike the minivans.
Having the car sit a couple months is not good, but it is a hell of a lot better than the alternative.