Blockchains don't move. There are now two blockchains that share a common history. What is moving is the HASHPOWER: the computers that add blocks to the blockchain are moving more and more to hashing the Bitcoin Cash blockchain and less and less on the Segwit chain. Bitcoin Cash could survive with minority hashpower because of big blocks.
Segwit Bitcoin will quickly turn to dust if it loses too much hashpower because it won't be able to process transactions with the 1MB limit.