If that happened then probably investors with weak hands will sell their Bitcoin because of fear. But still, many investors too will take advantage that price to buy more Bitcoin because its an opportunity for people who missed to accumulate before the price reach an ATH before.
Anyway, I believe its not going to happen for the price to return back to $8k value (though there's a possibility). Because currently the standing of Bitcoin is different from before, adoption is already happening and users are growing. Hence if the price will move below $20k, its expected that many investors will buy back, and majority of those people are aware of the history of Bitcoin.
when bitcoin is back at $8k, it's a big disaster for longtime investors, hope is gone. the taste has returned to ancient times where investors have become homeless. but from the other side there will be many new investors who are ready to become successful people in the future. I still doubt the statement that bitcoin can drop back to the price of $ 8k, but that could be a possibility if the Russian war continues to spread to other western countries.