I mentioned it below, but Karlsruhe has not only managed to hang on to its city wide standard gauge system, but KVV has been expanding its reach and ridership steadily for the last 15 years, with a number of innovations.

Not everyone threw away what they had.

By the way, I think Strasburg/Strasbourg uses the same type of train - they are very quiet, very convenient, but not that well suited for heavy ridership somehow. Just an impression for a couple of years ago.

Not everyone threw away what they had

For very different reasons. If you have experienced a ride on the East-Berlin tram before 1990 (during the GDR era) you will remember one. They couldn't abolish their tram because the socialist subjects had to wait more than 10 years until being rationed a car. So buses and street cars had to do.

In second-biggest western cities such as Nuernberg or Karlsruhe the tram was kind of tolerated for decades, though often majorities of car drivers were hostile to it. The main argument against it was municipal deficits in comparison to poor ridership/comfort and so on, but the real reason is, and was, that they were hindering individual (car) traffic.

The Karlsruhe region is an exception in Germany. Most regions could learn a lot from the planners of the Karlsruhe-Bretten-Pforzheim rail system, which is exemplary in entire Germany.

Unfortunately it is true what someone said: "Car drivers love transit. The others should give up driving and change to transit. The ultima ratio is, and is to stay, "cars first".

Transit will not work as an incentive, it will definetely not get drivers out of their cars; that is wishful thinking. Restrictive measures are necessary (and will not happen since in a democracy those who implement them will be voted out of office).

Our great poet Heinrich Heine knew it - already in 1843 - when he wrote:

"Womit man einlullt, wenn es greint,
Das Volk, den großen Lümmel."

He didn't know cars, of course. But he knew the people.