That’s interesting. Our winters are often wet and annoying. You don’t see many roadies out there before at least February. To be honest, I don’t think I’ve ever seen a proper road bike with mudguards in the wild.
And yes, once your winter 'proper road bike' has mud guards, tyres with treads, and an all-weather-riding design people might start calling it an 'adventure bike' or 'gravel bike' instead.