If it's metal the salt will eventually "kill" it. While not a Bolt, my Chevy Silverado is being slowly eaten by the salt on the roads in the winter months up in the mountains. I take it home once a month for 4 or 5 months when there can be salt on the roads and then drive it back down to the flat lands and run it through a carwash that washes under the body/frame.
Rusted out fender well on the drivers side, rusted out rocker panel on the driver's side. Brake lines rusted out years ago and were replaced with coated brake lines. The big U bolts that attach the rear axle to the springs are really badly rusted. One broke a month or so back and I've replaced both of them on that side. I bought 4 so I could replace them all and I need to get on with replacing the passenger side u bolts now, before one of them breaks.
Power steering cooler lines rusted out. The frame and things that bolt to the frame look pretty sad. Currently looking at a new truck now and hate the thoughts of driving it home to visit in the next few years.
I am so glad I don't live up north and can enjoy my other cars down here (in the flat lands of VA) without having to park them for the winter months to keep them from rusting away on me.
On most cars the end of life comes when the engine parts wear out beyond repair. On the Bolt, undercarriage rust might be the fatal condition rather than the drivetrain. But today's cars are much more rustproof than they used to be. Even here in Minnesota, I've had cars go well past 200K miles before showing significant rust.
I bought a $20/month unlimited # of washes plan for Dec-March. Typically I washed it at least 2 times a week.
Do nothing on a modern car and after 7 or 8 winters you'll see very noticeable signs of corrosion. One reason I dislike the idea of buying a very expensive vehicle that will get driven four seasons.
Some Cybertruck reservation holders brag that the stainless steel body will never rust. Guess what, salt water attacks stainless too.
With a pathetic 6 year rust warranty on the car and a thousand pound battery hanging between steel frame rails... yes I am concerned. Was actually primary reservation when buying the car, which replaced a rusted out 2007 honda fit (previously welded and no longer able to pass inspection).
"Sleds" (snowmobiles) are very popular here in far northern Maine, and one offshoot of the sport is "grass drags" - snowmobile drag racing on turf. Somewhere down the line maybe some enterprising mechanic will adapt the drive train and battery pack from a rusted out Bolt to drive a track on a tube chassis. . I'll bet it would be quite a drag racer on grass, with the battery pack adding traction...