The idea of Indonesia banking its fighter force on US warplanes is simply ludicrous. I don't think Indonesia has any more appetite for a high degree of dependence on US defense equipment given the history of US arms embargo on the country. In the early 2000s, US arms embargo effectively grounded the Indonesian Air Force's F-16s, effectively eliminating its primary (really, entire) fighter fleet, a condition which was only mitigated with the arrival of the Russian Sukhois.
Note that prior to this, Indonesia had actually planned to build a fighter force composed entirely of F-16s, with 80 examples planned. But the embargo proved that the US is an unreliable supplier. And once bitten twice shy, it now seeks to avoid dependence on one supplier. Neither the public nor the political establishment would accept a return to such a time since it had been taught the harsh lesson that when you depend on the armaments of one country, you'll have to obey its policies and dictates, and no country that has to obey another can claim to be truly sovereign.
Of course, I don't doubt that this policy is partly maintained by officials seeking to secure kickbacks from procurements, it is definitely a motivation. Indonesia is not like Singapore, its officials cannot just pay themselves millions over the table. The public would lynch them if they ever attempt to give themselves such a pay raise, so they have to skim them under the table. Malaysia - and pretty much the rest of Southeast Asia, really - is also in the same straits.
Of course, this isn't good since it lets officials get used to breaking the law. What I'd like to see happen is for countries like Indonesia and Malaysia to be more like the US where officials don't receive kickbacks or bribes and instead secure golden parachutes and run the revolving door of government and business. Instead of taking cash for making government decisions, they should instead take speaking and consultation fees. If these countries can reform their political culture in that direction, it will go a long way towards cleaning up their corruption reputation and perhaps approach the US ranking in the Corruptions Perceptions Index, the US being one the cleanest countries globally according to the index.
Of course, it still wouldn't be Singapore, but that's unrealistic for large and populous countries to aim for in the first place. Instead, countries like the US or Japan provides a better model for managing political corruption and diminishing its perceived impact. Such reforms would also professionalize arms procurement, giving the public greater confidence in the quality of defense spending.
I understand Indonesia stand in acquiring military hardwares from various sources, ID/India/China have similar pattern. They all are too big to rely on one source. Self reliance at least for the major equipments is the best option. Naturally, they all big nations with abundant sources and domestic market. Why give their domestic market for others?
Even if they can build inferior equipment will be not a problem. They already have natural detterent efect.