[geofft]

Apart from bandwidth limitation: the Chinese miners presumably make and value their profit in traditional money, by converting mining rewards. (If nothing else, they need to pay for the mining operation somehow.) A fall of the value of Bitcoin in traditional currency, e.g. due to a lack of market confidence, impacts their profits very directly. Miners, typically, don't want to hold Bitcoin positions themselves.

So they are incentivized to be extremely risk-averse to anything that could affect the Bitcoin exchange rate, and will only be excited about code changes when not changing would be clearly worse.