What? Beijing is no ghost city. It’s really crowded. Did you go on Line 1 Subway during rush hour? I’m from Dallas and once you drive a couple of hours from the city proper, you will find vast empty spaces, just like Dallas. However, the Central Business District is jam-packed 24/7.
Line 1 was not crowded. I spent most of my subway time on Line 2 and Line 5, followed by Line 10 and Line 1 (and then the Airport Express, of course).
I started each day at 5 AM and rode on and off until most of the lines closed around 21:00.
I also rode the public bus system extensively. Some buses were full, many were empty.