Why Ranger and Wasp remained experimental carriers

Were Ranger and Wasp merely compromised small carriers, or meaningful experiments shaped by treaty tonnage limits?

They were successive small-carrier experiments whose tradeoffs in air group, protection, range, space, and stability helped show what a viable fleet carrier required.

Standard and full-load displacement are different measures, and the relevant treaty clause was the modernization allowance rather than an exception for fuel. Ranger and Wasp were successive attempts to produce a small fleet carrier, forcing protection, range, air-group capacity, and stability into limited displacement and internal space. Ranger exposed how badly the concept could fall short. Wasp made enough progress to see combat, but her lack of torpedo defence left her acutely vulnerable to submarine attack, and the navy did not repeat the design. Both ships were experiments in finding the smallest workable fleet carrier, even though neither introduced revolutionary technology.