The oversubscription ratio (not everyone in the same area is online at the same time).
The acceptable cost of broadband, measured as a percent of monthly GDP.
The minimum bandwidth in Mbps Starlink will provide.

SpaceX has a new Starlink user terminal and dish factory in Texas. SpaceX has designed a rectangular flat terminal that will be lower cost and higher performance. SpaceX should be making millions of terminals by the end of 2021.