1) The United States could not begin to improve the defenses of Guam or the Philippines before 1937 because of treaty provisions. The US was forbidden (by Article XIX of the Washington Naval Treaty) to improve defense facilities in the Philippines or Guam from August 17, 1923 to December 31, 1936. (The end of the treaty). Under the Treaty, Pearl Harbor could be developed; Cavite could not.
2) By that time, the Tydings-McDuffie Act (Philippine Independence Act (Pub.L. 73–12)) provided for Philippine independence within 10 years and transfer of US assets, including military assets, to the new country within 10 years of its Constitution.
3) The same statute (Section 11) directed the President to begin negotiations for a treaty for perpetual neutralization of the Philippines.
4) In the period 1936-1940, Congress would not allocate funds to improve the base at Cavite which would be surrendered within 10 years while legally required to seek neutralization of the Philippines.
The United States, the British Empire and Japan agree that the status quo at the time of the signing of the present Treaty, with regard to fortifications and naval bases, shall be maintained in their respective territories and possessions specified hereunder:
(1) The insular possessions which the United States now holds or may hereafter acquire in the Pacific Ocean, except (a) those adjacent to the coast of the United States, Alaska and the Panama Canal Zone, not including the Aleutian Islands, and (b) the Hawaiian Islands;
(2) Hong Kong and the insular possessions which the British Empire now holds or may hereafter acquire in the Pacific Ocean, east of the meridian of 110° east longitude, except (a) those adjacent to the coast of Canada, (b) the Commonwealth of Australia and its Territories, and (c) New Zealand;
(3) The following insular territories and possessions of Japan in the Pacific Ocean, to wit: the Kurile Islands, the Bonin Islands, Amami-Oshima, the Loochoo Islands, Formosa and the Pescadores, and any insular territories or possessions in the Pacific Ocean which Japan may hereafter acquire.
The maintenance of the status quo under the foregoing provisions implies that no new fortifications or naval bases shall be established in the territories and possessions specified; that no measures shall be taken to increase the existing naval facilities for the repair and maintenance of naval forces, and that no increase shall be made in the coast defences of the territories and possessions above specified. This restriction, however, does not preclude such repair and replacement of worn-out weapons and equipment as is customary in naval and military establishments in time of peace."