It's pretty silly to compare the average speed of the Shanghai Maglev. It's like a 7 minute trip with 1 minute at top speed. There's several, traditional HSR, routes in china with faster average speeds.
* None of these average speeds would make Chicago-Houston competitive with air. Even if you add the hour on both ends for the air trip, the fastest train in China operating above the Chinese speed limit still loses to Southwest Airlines.
* None of these average speeds make a 300MPH average speed train any more realistic.