Are you aware of any health insurance plans in the US which don't have an open enrollment period? I think this is standard across the industry as a check against adverse selection, but most of the information quickly available is ACA-focused, where it's definitely a feature; since open enrollment is extremely beneficial to insurers, I wouldn't imagine them talking up alternatives.
It's true that there is a list of qualifying life events that let you change or acquire insurance outside of open enrollment, but none of them look like "because I don't like my insurer" to me.
It's true that there is a list of qualifying life events that let you change or acquire insurance outside of open enrollment, but none of them look like "because I don't like my insurer" to me.