That scenario would lead to a price split where the vast majority of hashpower and value was with BTU.
No, it's not. It's completely unknown what would happen to price depending on
random people power dumping 200,000 coins at once on each chain. Hell, both chains could crater to nothingness.
That would not make any sense if you apply human nature in the equation. If you hold 200,000 Bitcoins would you dump them on the other chain you do not like just "because" or are you happy with the doubling of your stash? It would be very illogical of them to start a dumping war because no one would win.
Except it already happened in Ethereum.