It is indeed often the case, but there are real-life scenarios where this is false (e.g. 480p DVDs probably look better than YouTube 720p because the latter has a much lower bitrate) and the causal relationship arguably exists in the opposite direction: less bitrate is required to make lower-resolution videos look decent, so lower resolutions tend to be preferred when people need to cut down on bitrate.
It is indeed often the case, but there are real-life scenarios where this is false (e.g. 480p DVDs probably look better than YouTube 720p because the latter has a much lower bitrate) and the causal relationship arguably exists in the opposite direction: less bitrate is required to make lower-resolution videos look decent, so lower resolutions tend to be preferred when people need to cut down on bitrate.