Because Indonesia has a massive population, far more people than the US and much more densly populated. It's internet users are vastly mobile as opposed to desktop or LAN connections. The US geographic landscape and computer use landscape are entirely different.
It has everything to do with the lack of competition. US tax payers paid $4 billion to AT&T in 2004 for fiber to -every- home. And that was never delivered, yet they keep getting more money. This is regulatory capture.