It is the policy of the State that: the orderly development and use of land and structures requires comprehensive regulation through implementation of planning and zoning controls; and local governments shall implement planning and zoning controls. To achieve the public purposes of this regulatory scheme, the General Assembly recognizes that local government action will displace or limit economic competition by owners and users of property. It is the policy of the General Assembly and of the State that competition and enterprise shall be displaced or limited for the attainment of the purposes of the State policy for implementing planning and zoning controls as provided for in State and local law. The powers granted to the Commission and district councils under this section may not be construed to: grant to the Commission or district councils powers in any substantive area that are not otherwise granted to the Commission and district councils by State or local law; restrict the Commission or district councils from exercising any power granted to the Commission and district councils by other law; authorize the Commission or district councils to engage in any activity that is beyond their power under other law; or preempt or supersede the regulatory authority of any State unit under any State law.