The cities rebuilt after WW2 are actually the worst for walkability and overall pleasantness, though in part of course they incorporate elements of the original city and in some cases they've even been rebuilt exactly as they were. Luckily they're a small minority of all European cities, although many jewels are lost forever.

Partly. It depends on how far you go back. The areas within former city walls (where people used to live) have pretty organically developed to being inner city business centers for most larger cities. Rebuilders honored this, but the initial development was probably not conceptionalized as a whole by a human beforehand.

This relates to the fact (and I think this is what the parent poster is referring to) that these cities started way before any cars or bikes existed, so cities had to work for pedestrians.