While any of the bonds issued by the authority remain outstanding, the powers, duties, or existence of the authority or of its officers, employees, or agents or of the various county boards of education, city boards of education, or governing bodies of independent or quasi-independent districts or systems shall not be diminished or impaired in any manner that will affect adversely the interests and rights of the holders of such bonds, nor will the state itself so compete with the authority. This part shall be for the benefit of the state, the authority, and the holders of any such bonds and, upon the issuance of bonds under this part, shall constitute a contract with the holders of such bonds.