"The major Chinese cities generally have very developed and efficient systems of mass public transit, reducing demand for rideshares (and cars in general)"

This depends on your frame of reference. If you're comparing with SF, sure. If you're comparing with London or New York, less so. In London, the underground is faster than private car for many (most?) daytime journeys. In Beijing and Shanghai, a private car is almost always faster. Subway stations are spaced too far apart, and the walking involved in changing lines is pretty long. Buses are slower than cars even at times when bus lanes are active.

"While China is a large country, not everyone can afford an automobile or a rideshare service."

The people who don't have cars are precisely the people who use rideshare services.

Compared with the West, in China, ridesharing fares are lower, and the cost of owning+operating a car is higher. I ride Uber 10-15 times per week. The total cost of those rides is 20%-30% of what it would cost to lease and operate my own car, even if parking were free (which it's not).