Well, the USA is only ~250 years old and most of its planning was done in the past ~150 years, whereas most European cities date back to the middle ages or even before that, growing much more organically, often around a castle, wall, church, or all of the above. It's only in the past 100 years or so that cars are a thing.
But the other is just different approach to planning. I live in a relatively new, so-called "vinex" suburb [1], a neighbourhood built according to certain specifications - relatively small gardens, bike- and pedestrian safe, the only cars you see are the ones heading to- and from their house, the rest is redirected to a ring road. And, very low uniformity in housing designs; common themes, but a lot of diversity.
That said, at the moment we have a massive housing crisis - we need 100K houses in the next decade, probably more - and I feel like the only way to solve it is to build boring houses, big apartment complexes, that kinda thing. The alternative is population reduction, but nobody wants that.