Hard to predict how most people would act under such situations but yes, if the price of bitcoin in comparison to fiat does spike due to the crash, then they might take out their money and use that to take advantage of the situation, like use it to buy cheaper real estate.
Nothing too scary IMHO. If BTC price goes down due to all the money flowing out then that's just opportunity for more people to buy. Remember if it rallied during the crash more people are more likely to trust it.
The question is also full of uncertainty. It should not just be a matter of what we can do, but rather what we can do to avoid an economic crisis?
The 2008 economic crisis began in the United States and was exported throughout the world. why did this happen?
Global financial system which pivots to the US. Derivative products produced by the US are sold to various countries in various forms. Began to be sold on the capital market with its free-market principle to become an instrument of development, such as foreign debt-laden with political content. There is almost no country that does not have financial relations with the US.
Second, the economic system and global trade. Many countries in the world open their markets to large corporations. Let them develop the economy without giving protection to the people's economy and let the people become workers. Allowing income depends on the results of purchases of goods in foreign countries. This economic structure makes the economic structure vulnerable to crisis. This is what caused many countries affected by the crisis in the US because many large US corporations went bankrupt due to the crisis that controlled the economies in these countries.
Third, the world political system is dominated by the US. Besides the US being the dominant actor in global financial governance, the US is also dominant in global politics. The US, through its policies, is pushing the world economy open to the US market.
If we predict the price of bitcoin or altcoin will go up or down we don't know when it will happen and what the conditions will be. Now the governments of each country begin to square off issuing their respective stable coins and cryptocurrencies. Of course, it will shift the crypto market map even though it is still dominated by bitcoin.