It's not quite that simple - the chain will need to be forked with a protocol whose algorithm doesn't allow these miners to continue to dominate. And achieving consensus on that in the heat of the moment will be non-trivial.
Any fork that continues to use SHA-256 will be a trivial target for attack by these miners; they won't blindly continue to mine the "defunct" chain.
the bitcoin gold algorithm, achieving consensus will be possible, because is a threat to bitcoin existence (user activated), won't be "that simple" but will be another attack and bitcoin will emerge stronger.
It's not quite that simple - the chain will need to be forked with a protocol whose algorithm doesn't allow these miners to continue to dominate. And achieving consensus on that in the heat of the moment will be non-trivial.
Any fork that continues to use SHA-256 will be a trivial target for attack by these miners; they won't blindly continue to mine the "defunct" chain.