Yeah, this was my initial confusion with the article and many of the comments. When I read the doc by Musk, I assumed, that the tube 'floated' over the pylons. The author seems to have assumed the opposite. The problem is that they are both assumptions.
When making an argument, sometimes it is good to make an assumption and then prove the assumption is false... sometimes it is just a straw man.
The tube does float (longitudinally) over the pylons, in the proposal.
The tube will be supported by pillars which constrain the tube in the vertical direction but allow longitudinal slip for thermal expansion as well as dampened lateral slip to reduce the risk posed by earthquakes. In addition, the pillar to tube connection nominal position will be adjustable vertically and laterally to ensure proper alignment despite possible ground settling. These minimally
constrained pillars to tube joints will also allow a smoother ride.
When making an argument, sometimes it is good to make an assumption and then prove the assumption is false... sometimes it is just a straw man.