Well, their chances are there: BCH would remain SHA256. And 100% of the blockchain's hashrate is running on SHA256.
Any Equihash would just run on some GPUs that formerly did ETH or something else. Since ETH turning POS.
I don't like that perspective!
We are at Height 488317 so this would be 6467 blocks ahead, or (10 minutes each) 45 Days ahead. Six weeks.