Having lived in Hawaii for over 30 years, I believe that I remember correctly when I point out that those few "legal" short term rentals in existence in the Kailua area were once all illegal themselves, and that they essentially got "grandfathered" in by applying for a permit and a Transient Accomodation license.  And to get the permit, you had to demonstrate that you had in fact been engaging in illegal short term rentals.  So - if you really want to level the playing field, then even all existing legal short term rentals should be eliminated.  My preference, however, would be to allow true "B&B" type rentals, where in fact the owner-occupant of the property actually lives there, has a homeowner's exemption to prove it, and only rents out rooms or a portion of the house that they live in every day.  It is unlikely that kind of situation would really reduce the long-term rental pool, would preserve the residential nature of our neighborhoods, and bring in needed tax revenue.