The Bitcoin network is not controlled by any central authority. Each machine that mines Bitcoin and processes transactions is considered a part of the network, and all mining machines work together. So in theory, no central authority can rig this monetary policy and it is less likely to cause a crash. It is because of this security that people use Bitcoin so much
Yes, bitcoin is decentralized so no one can control bitcoin and or increase the number of bitcoins. But even though bitcoin is decentralized, authorities such as countries can still make monetary policies towards bitcoin, such as levying taxes or regulating how bitcoin is used.
But as far as I know bitcoin will die if all miners turn off their computers.