I never found the idea compelling because all the distances spoken of were so short that getting to and getting out would eat much of the time saved.

that and this example is a paltry little tunnel in no way useful without the required safety of a parallel tunnel and such.

the real game changer going forward is still autonomous vehicles. combined with EV technology they will disrupt both the automotive industry on a scale many do not fully imagine as well as public transport and providing freedom for people to live further apart. it will give even more people the freedom of travel