That is the point, the whole east south asia did not put so many money to military expenditure. PH has 1.1% of the GDP about 2.9 billion dollar. It is the willing to buy weapons. If the willing is low, there is no weapon market. If the budget is limited, to buy some cheaper weapon is the choice, though US weapons are also expansive. In this case, PH is not a customer of JP. PH needs aids, may be some old jets or boats, not buy new ones.
Another thing, the people has more money than the party in China, the private sector is stronger. No government is rich, they are all in debts. Is US government rich? It has 177419534XXXXX dollar debts. Chiese govenment is also in debts, the Japenese...oh, they are almost bankruptcy, indeed they have been.
PH is under US protection for more than 100 years. Indeed there is no needs for PHs to put so many money in militray sector. The world is not 100 years ago, Victoria era was long gone, occupy a country and rob money is not the highest interest. Conflicting with China is only a method to divert the attention from the domestic problems. The PH has only one boss, not two. Japanese again? That may cause the conflicts in your own country, if JP and US have different policy to PH. Just do not try that. So, I said, it is not an option to JP. The re-interpretation of JP constitution released the right to JP government to build alliance alone, not under the US flag. US will not be happy to see his ally is taken over by his little brother, that is rebelling.
The CPP is the only one who can be the governing party, They have no chance to divert the attention, because the domestic problems have to been solved by themselves, sooner or later. Indeed, we have not oversea towards plan, but still focus on the domestic problems. That is the differences brought by the political system.