The physics are sound but the engineering practicalities may not be. For example, the original design requires air to be actively pumped from in front of the vehicle out the back, because even in low pressure the air resistance is problematic. You can't get much lower air resistance without a much more complicated, and thus expensive and failure prone, tube.
The issue of the pylons subsiding is also rather severe. On Japanese high speed railways they inspect every metre of track every night, and repair it as necessary. Repairing subsided track is relatively quick and easy, you just shove some spacers under it. Fixing a subsiding pylon... It's an engineering challenge that needs a clever solution.
The economics are also questionable. The capacity is low, even with multiple cars. High speed rail carries hundreds of people and their luggage in comfort, and in Japan it leaves every 15 minutes. The new maglev trains are going to start at 550kph and are expected to reach over 900kph in time, once the company has experience running them and maintaining the track. So actually they are going to run much larger trains at similar speeds to this design on a much cheaper, lower tech track, and presumably with their usual excellent safety record. And they are building it now, with proven technology.