I don't think it's wrong but in my area of the country there isn't the shortage of CNA's as there is of nurses. It's a supply and demand thing they don't use many nurses around here either just every now and then.
Also knowing how to give a shot are start an IV is not the same as knowing the medications and reactions, following a carepath, care plan whatever it's called and having the knowledge base. Yes CNA's are part of the team but are you saying nurses aren't needed because you can do everything as a CNA? I've taught 12 yr olds to give their own shots so should they be allowed to do work and take care of patients?