Changing to it immediately would be impractical, but a steady transition would be pretty easily feasible, outside of the political concerns.
It's not like dense, mixed-use areas don't exist in the US -- NYC being the most obvious example. They're just uncommon because regulations force them to be uncommon. Where they do exist they work fine.
It's not like dense, mixed-use areas don't exist in the US -- NYC being the most obvious example. They're just uncommon because regulations force them to be uncommon. Where they do exist they work fine.