Generally, if you watch a fair amount of German public TV (ARD and ZDF, or the sub networks)....about once a month, you will get a dose of some documentary or news piece which talks to the issue of a car-free society.
It's not openly talked about when this idea started up but I suspect it came in the early 1990s, after some German activists watched a couple of Hollywood productions where the movie portrayed the future without cars.
The general idea is that you'd go and develop bike-paths, painful decisions for car owners, improve tram and bus lines, and make the whole bus-train business 'free' (something often discussed).
How close are we to this idea? To advance the concept, Chancellor Merkel agree to five to six German cities (some large, some small) in getting a fair amount of funding to create 'free' public transportation. Buses and trams would be added, and all of this in the cities selected...would be free. A test would be accomplished and in five years....results would be discussed.
Most think the tests will go positive, but the cost impact will be something that simply cannot be accomplished German-wide, unless you really raised taxation, and the rural parts of the nation would be left to survive with nothing changed.
Public discussion over this 'fantasy'? Just to suggest that all gas/diesel new car sales end in 2030...is taking some Germans to a shock level, and it's hard to imagine the whole nation going to battery-power by that point, with only used gas/diesel cars left.
The position that you see is that some politicians would like for a push by the government to make people adjust their lives to a new lifestyle. Journalists do their part to advance the idea of car-free civilizations existing, with the idea popping up and suggesting how it'd all work. In their mind, there is nothing ever negative about this car-free city idea. I tend to agree but just don't see this maturing at the rate they suggest. And if you live 40 kilometers outside of some car-free-zone....the odds are that you will find the rules established to control your entry (via a car) to make your life miserable.