I don't think anyone expects that from the rural population either. It would simply be enough if politics, including in the green spectrum, accepted that a larger part of the population has routes that cannot simply be covered by bus or bicycle. And instead of a campaign against the car, then address the second part of the problem. In the countryside, many routes could basically be covered by bike, with an e-bike it is enough. Unfortunately, bike paths are designed for tourists, if at all. Often you are simply sent onto the country road where cars come roaring up from behind. And if you look for a safe route through the forest yourself, then you just have dirt in the rain and nobody clears it in winter. With little effort, much could be improved there.
I completely agree with you, this idea that a large part can leave their car standing and use public transport is unaffordable for the majority of people in Germany, who live in rural areas. You have to get creative and install demand-responsive buses. A good thing, so that people without cars can be mobile in the village. And the bike paths are already well developed in the city, but in the countryside, as you say, there is definitely a need for improvement. Road repairs also cost a bit, but surely more people would use the bike. Unfortunately, our politics often only have the Berlin-Mitte faction in mind, who ride through the big city without a car on their rented bike. For them, often one-third of a busy street is expanded as a bike path. Politics should of course step out of this big city bubble and especially keep the rural areas in mind.