No, but my impression is that even in cities in the US which have the density to support good systems, the systems tend to be... not great. I go to SF from time to time, and it's the only place I regularly have to resort to lyft/uber/etc, because the public transport system just doesn't seem... very useful. And I'm coming from Dublin, a city with a pretty bad system by European standards.

And it's _possible_ for public transport to work for fairly low density suburbs; I think some places have had success with small feeder buses feeding larger buses or trams.

Also, of course, urban planning can be improved. And tastes can change too; my impression is that the very large McMansion type houses are getting somewhat less popular in the US now, and they're a big contributor on two grounds (they exacerbate the low density problem, and they're expensive to heat and cool both due to sheer size and to generally relatively cheap construction prompted by the sheer size).