There is a good reason to develop at least one rhinovirus vaccine, though: so we have the expertise to deal with a bad rhinovirus strain if one should arise later. The coronavirus experience - SARS, MERS, and now COVID-19 - seems to suggest that such groundwork on common virus types would be a good idea.
The ethical case for vaccinating against rhinoviruses isn't really there, even if it were viable to do so.