You raise some interesting questions... I have some in return.
My biggest question is how it would be less costly to build and operate. Consider that the maglev uses electricity to power the vehicle, I agree that you have the costs of installing and maintaining the electrical components. That said, to be a "Zero Emissions" transport, the ground effects train would also need electrical power supplied, relying either on inductive/capacitive power or a physical connection--little different from maglev. Honestly I see no significant cost differences between the two methods.
On the other hand, using a form of gas-turbine engine to provide both thrust and electrical power, the trackage would become much less expensive but we retain our reliance on fossil fuels when we really need to find ways to eliminate it. The advantage would be that less fuel is needed to attain airspeed because the vehicle doesn't climb out of ground effect and doesn't have to burn additional fuel to achieve flight altitude--the greatest fuel cost in aviation today. At no point can we rely on battery power today due to the weight and cost of any battery pack powerful enough to offer any significant range.
