That’s my dream too, and why I’m actually sort of onboard with Musk’s vision for car metros. The issue is that I’m 100% sure they’d also want to expand surface level car infrastructure to facilitate that network.
My centrist compromise that I hope will take off in European cities over the next decade is that most two lane city streets will become one lane one way systems with protected bike lanes, pavements and trees taking the space that’s been freed up.