They figured out if you just pay the decision makers some money they will sell everyone out. See congress for examples.
https://www.abc.net.au/news/2019-02-08/chinese-billionaire-h...
https://www.afr.com/news/world/asia/chinese-aid-funded-1-mil...
https://www.abc.net.au/news/2018-05-22/chau-chak-wing-un-bri...