I'd say commercial automobiles probably have a net positive effect. (Though their impact on pollution and climate change can't be discounted.) But daily life in walkable and public transitable European cities is so, so much nicer and healthier than in most American cities. I'd trade ubiquitous personal automobiles for that in a heartbeat.

There's still plenty of cars in europe. Biggest advantage of europe is even the major cities are only so large in footprint, like even berlin is barely over a dozen miles across. Major US cities could be 40-60 miles across. Greater LA maybe over 100 miles across depending on how you measure, all contiguous development. The northeast corridor is nearly contiguous urban/suburban development over a ~450 mile snake from washington dc to boston. Makes a little 10 mile rail line in berlin capture a much greater share of potential trips within the berlin urban area than a 10 mile rail line pretty much anywhere in the US. LA has a light rail line that is over 50 miles long.