GDP per capita is more than 4x in Netherlands (on a PPP basis). On a straight per capita basis, it’s even higher. See, e.g., https://tradingeconomics.com/indonesia/gdp-per-capita
Also, the problem here mostly seems to be not money, but government. As the article states “Nobody here believes in the greater good […] There is no trust”. Short-term, how much more expensive would it be to get clean water from the rivers flowing into Jakarta, instead of from those illegal wells?
Less cheap to transport (e.g. bricks) or less durable (e.g. fruit) goods move less easily, and labor moves least easily.
Consequently, it is way cheaper in poorer countries to have personnel, to pay people for repairing stuff, etc.
(I think I misread your comment and others might too, so I'm leaving this here)