FWIW, I haven't made the parent comment's sort of experience in either Berlin, London, or Paris. So it might be somewhat specific to New York.
And I have trouble understanding what you are actually suggesting, but it seems to be an entirely technocratic take ignoring what actually makes cities liveable, with possibly some dehumanisation of homeless people thrown in for extra discredit?
I've managed to make a (insert politically correct term for "gypsy" here) beggar in Paris turn around and walk away a few seconds after she bee-lined towards me with my scowl, which makes me wonder what look I had that was so effective...
In US cities it seems the norm is to never say a word to strangers about anything, ever, so it then follows that anyone who does talk to you is more likely trying to grift you. Which makes you even less likely to talk to strangers in the future, in a vicious cycle. I've never actually read Jane Jacobs but I'm pretty sure this isn't what she was interested in preserving. I don't know if it's technology, population churn, or what.
I would disagree that all US cities are like that. In the midwest, people will talk to strangers on the train or street in Chicago. Even in the coastal cities there have been instances where I’ve spoken w people around me if something funny or odd is happening.
And I have trouble understanding what you are actually suggesting, but it seems to be an entirely technocratic take ignoring what actually makes cities liveable, with possibly some dehumanisation of homeless people thrown in for extra discredit?