It sold very poorly. Despite all of the YouTubers and social media posts calling for smaller iPhones, the real demand for these is very small.
The older demographics generally prefer larger phones because they have larger screens, which are better for aging eyes.
You also have to understand the psychological profile of us "utilitarian" iphone users. We only get one when our hands are forced either hardware failure or forced software obsolescence. The iphone mini came to market and was discontinued all in the time I was still using my SE.