So this is obviously a several year old proposal from SpaceX in which they claim that their Starship is capable of being used as a means of traveling anywhere in the world in under an hour.
A shiny promotional video can be found here. The obvious problem here is economics, in the same fashion that kept the Concord from being anything more than a French/British vanity project. But then economies of scale help, not to mention the fact that Starship can carry a much larger payload and spread the cost much more easily.
Another factor that could affect this is the use of VTOLs to heavily supplement traditional aircraft for shorter flights. Either compound helicopters or tiltrotors are fast and efficient enough that over shorter distances where they can land closer to the final destination they could easily be superior.
I'm not sure how this would really be affected by decarbonization of energy and a switch to electric propulsion for most things, but it is likely that it would limit both traditional aircraft and this more exotic mixed approach about equally. Both would require synthetic fuel production because batteries are too heavy for aircraft and obviously don't work for rockets.
For a future Earth, is this plausible?