How would they plow or treat those roads in the winter??
Pretty much like the others. I live on a gravel road (in Michigan, in the U.P.). We get plowed daily. They don't generally salt the gravel ones. Our road is actually better with a nice snow matte on it than it is in the summer (washboard).

This practice doesn't apply to all roads, by the way - the link seemed kind of short on details, unless I missed another link within it. Just the really bad ones that they can't afford to repave - probably nothing anyone would go out of their way to bike on in the first place. There were one or two near here that they reverted (or are going to?) until they have funds to repave them. For driving, a good gravel road is way better than an exploded paved one. If you don't mind the dust and the washboards. They need to be graded periodically, and they oil our road right in front of houses, and on the hill we're at the top of. The first monster truck that decides to spin out on it pretty much wrecks that for the summer.

When I ride my road bike, I drive the 2-1/2 miles to pavement. And I don't bother washing my car much.