Evacuated Tube Transport could take you around the world in just 6 hours

The problem here is the "evacuated" part. It's hard to hold a vacuum in a large vessel: think of how few giant vacuum chambers exist. Most of them were built for the Apollo program, and just get maintained. How hard is it to maintain a meaningful vacuum in thousands of kilometers of tubing? Every weld, every seal, have to be spaceship-quality.

Then there's the tube itself. To hold off sea-level collapse pressure, you'll need a relatively stout tube, probably with ring-stiffeners every so often to keep any buckling from ruinging a continent-long length of tubing.

So, pumping the tube system, the tubes themselves and the valves, seals, and welds, plus ongoing intensive inspections. This is like jetpacks, helicopter taxis and fusion power: always at least 10 years in the future.