You are forgetting that the hyperloop design naturally lends itself towards being placed on separate, comparatively cheap pylons, since the structural rigidity and relatively low weight of the tube sections allows them to be far more self-supporting than maglev tracks or even traditional rail tracks.

This essentially removes the requirement of flat land from the equation.

Also, remember that the hyperloop is really much more geared towards the American need: large cities are separated by much greater distances than Europe, meaning that a faster and cheaper per kilometer solution is needed than high speed rail.