There is generally no expectation and people typically budget time/$ for ubers or metro rides.

I had no car for 6 years and a car for 3 years. I'll offer rides IF we're somewhere far from a metro and it's on my way. But the perks of living in a city are the ease of transportation and it's generally assumed people are adults who can get around by themselves. I would agree that the "rules" change slightly in the 'burbs, but good manners would only extend to a metro station, not all the way home.