I'm all about having children "aspire to bigger things", but the pretend play involved in cleaning, play cash registers, cooking, etc. is just as important developmentally, if not moreso than playing doctor, vet, etc. Most toddlers spend a majority of the time in the home and other service industry settings rather than at the doctor. If they aren't imitating things they see, then there's a problem. I've worked with children receiving special education services with a wide range of abilities. For some it would be considered a huge success to become a janitor.