Yeah.

A lot of times, you will see things like “this new technology can be built elevated/underground really cheaply so you don’t have to buy the land underneath!” Except that’s not how property rights work in Western countries at all, and at a practical level things like emergency walkways or fire ventilation or maintenance passageways end up eating whatever the miniscule difference in right-of-way width is.

You also have the matter of the Gadgetbahn advocate convienently neglecting to mention that most of the cost of a typical subway system goes into the cavernous stations. They pretend the costs of a modern subway station is purely the cost per mile of tunnel, and that's the number they compare their pure cost per mile number to.

So the subway cost per mile includes stations, while the Gadgetbahn cost per mile doesn't include anything other than tunnel boring. Certainly not the costs of each ludicrous car elevator.