How is this "safe to assume"? Given the history of the world, and migration that is overwhelmingly to places that have seasonal freezing temperatures, this seems comically ill conceived.
I love winter, even though I don't partake of winter sports. I love cooler temperatures. It's a lot easier being comfortable when it's cold than when it's hot. The number of pests, diseases, and perils are just so far fewer.
I'm not going to say something as asinine as "people don't prefer to live in places without winters" because I know other people have different tastes, but an enormous number of us seem to rather like cold weather.
Relatively few in the US. The Bay Area is something of an outlier for having generally temperate summers and having no or rare snow in the winter. If your priority is "nice" weather year-round, it's hard to beat Northern California. The Pacific Northwest mostly qualifies too but, of course, it's wetter and grayer for much of the year which many find off-putting.
The western end of Western Europe also qualifies.
Only reason I can think of would be if the place had good skiing/snowboarding/snow activities, but you need decent mountains and snowfall for that.
Edit: NYC/Boston are outliers that have other exceptional offerings, especially related to economic opportunities. There is also inertia of being a place where people settled in first and set down roots, but I imagine most people would consider the weather of the upper midwest and upper PA/NY regions to be a negative.