they can open a 51 attack any time they want.
But as it stands, there is no singular 'they', so no 51% attack.
At least the Chinese will always win the consensus.
Like SegWit a lot of the Chinese miner was rejecting it and there is no doubt for that.
So, this will be affecting for slowly.
There is no singular 51% attack, there is 51% attack by grouping.
The Chinese philosophies tell me the different perspective.