[Animats]

I often see urbanists and young people fantasize about life in car free mega cities.

Yes.

Now go look at Peter Cooper Village in NYC.[1]

"The complex is designed as two large "superblocks", independent of the grid system that characterizes the majority of Manhattan below 155th Street.It consists of two large parks, one for each part of the complex, juxtaposed with modern red brick apartment towers."

[1] https://en.wikipedia.org/wiki/Stuyvesant_Town%E2%80%93Peter_...