If I were to ask most people I know offline, I suspect only a small number of them would know what a minisplit unit is. For most people, A/C is like plumbing. They do not think about it until it breaks. Learning that there are better options is just not something that people do.

That said, I was replying to someone from Vietnam. Assuming that things in Vietnam are similar to China and Japan, people will only heat or cool the specific rooms that they are using, rather than heating or cooling everything like how many Americans do things. Those in the US who cannot afford to heat or cool everything, who are likely very underrepresented here, would be those using window units, since they are cheap upfront. A minisplit would be cheaper over the long term, but the high upfront cost dissuades people in thing market from even looking at them.

Finally, I had Fujitsu minisplit units installed in my basement two years ago. They are far more aesthetically pleasing than window A/C units.