For many reasons, such as stealing electricity and having access to chip manufacturers, there are a handful of miners in China who have the majority of the computing power for Bitcoin. They can mine bitcoins at a cost that is less than for everyone else.
This creates problems because there are updates to Bitcoin that are needed, such as allowing the Bitcoin network to process more than 7 transactions a second (for reference, Visa does 40,000 a second). Unfortunately, this small block size rate means people have to pay extra fees to prioritize their bitcoin transactions to happen in the next 20 minutes.
The miners get to keep these additional fees, so they are incentivized to keep the network slow and people paying more. This is why the Chinese miners have rejected any updates to improve Bitcoin transaction rate, meaning bitcoin is slower and more expensive for everyone but the miners extract more money from the network. It's tragedy of the commons.