I get that we have to be open with tech. After all most tech seemed "impossible" "unrealistic" and "unfeasible" even a couple of years before they go mainstream.

But you have touched some use cases that are more frequent than most people think. London is a great example. My hometown Athens is much more closer to London as far as driving is concerned as opposed to LA or NY. I guess many other metropolis also.

How will AI brand A communicate with AI brand B about life critical decisions ? Hey we can either both crash to each other or kill that kid on the pavement. ( just an example , I don't want to go to the morality of the situation)

I assume there is going to be a "standard " . But have a look at your everyday tech. Standards are not easy. There are still WiFi routers/repeaters that cannot talk to each other nicely, just to give an example.

Usually in life critical systems you don't have interoperability issues because there is no interoperability. Huge fail-safe systems from a single vendor.