Without going back and doing quotes, here are a few comments and responses. Those following the thread will know to what.
Concerning the cutting of ordinary trains where high speed lines go into service: Remember that China's economy is still very much a top-down "Command" economy instead of the bottom-up "Demand" economy where service demands can only be skewed by government intervention, not determined by it. The change of services was commanded, but when done the demand was not there. At least the powers that be did wake up to some of the reality, as follows:
China's huge population is still mostly very poor. For most of the people except business and party elites, price is far more important than speed in determining trip choices. So, even in the areas where the high speed service exists, the high speed train's market is probably only a few percents of the travel market.
Concerning Calif HSR: The target speed is 220 mph operating speed with an alignment that will permit 250 mph ultimately for as much of the alignment as can be achieved. It has been fairly conclusively determined that when end to end rail trip time gets under 3 hours, the air service demand drops drastically. The 220 mph maximum speed is necessary for this to happen. If an alignment between Bakersfield and about Burbank was built that would permit 70 to 90 mph, an end to end all rail, except crossing San Francisco Bay, trip time of about 8 hours could be achieved. This is reasonably close to realistic end to end times if driving. Even at these speeds, a one seat ride should result in a huge increase in the rail share. However, to build a 90 mph alignment across the Tehachapi area would not be significantly cheaper than the 220 mph alignment. So, might as well build the higher speed line.
If you choose to build a 110 to 125 mph railroad, for much of the route it will be little to no cheaper than building a 250 mph railroad.. You will still need 100% grade separations, and many of the other thing you would need for anything going above 90 mph.