This is not a good example. Medical interns have a set time where they will then no longer be interns. Some people move to the majors after barely completing IOE at a regional, while others with over 10 years of experience at a regional are still not getting a call.
An economic downturn or terrorist event may leave you at a regional for your entire career (as many already know). Regional pilots shouldn't be paid with an assumption that all of them will move on to a legacy because that is not a guarantee.