I think most of that comes from the fact that American sports have playoff systems to determine eventual champions (and the uncertainty that entails) whereas leagues favor consistent performers (strongly correlated with the money a club can invest). If you see playoff-like national tournaments in European soccer (which happen in parallel with the leagues) those too tend to have a wider spread of winners.

At least in England, clubs are an integral part of local culture (see the emotions involved in a derby!), and the thought of “moving” a club to a different location would be heresy. I presume that it’s very similar in many other European countries too.