Few other vessels can. Aircraft carriers are capable of significant maintenance and repair while under way. However, aircraft carriers have shore support nearby in an emergency, a starship won't. Carriers still aren't big enough to make all their needed supplies, parts, etc.
Aircraft carriers have a similar size of crew complement.
Basically, we need to send a small city with all of its many occupations. Kelly established that for the mission duration's we are typically talking about, it was more economical to store all food rather than plan on growing any onboard.