This is a fair observation; Manhattan always feel to me very impersonal. However, I think the parent comment is referring to the Interstate Highway System cons

This is a fair observation; Manhattan always feel to me very impersonal. However, I think the parent comment is referring to the Interstate Highway System construction in the '50s (and the broader 'Urban Renewal' movement of that era), which razed many of the dense neighborhoods in smaller cities to make room for highway construction. The relevant comparison isn't Manhattan to Scarsdale but the life one could once live in Hartford or Newark to how those cities are today.