This sadness certainly will not last long, we all also know that if we have entered the crypto world, whatever happens we must accept it with an open heart because crypto does have a high risk.
This will depend on the percentage of assets you allocate to cryptocurrencies. There are people who are investing everything they have and putting all their faith in it so if it suddenly disappears, their lives could disappear along with the market. We have had many such cases in the past and the Luna crash in 2022 is a prime example, many people committed suicide just because of this crash.
Everyone is aware of the risks but in the end, they can't overcome their greed so I don't believe anyone can get over this pain quickly if the market disappears.
Although cryptocurrency has only just emerged, it can be said that many people have already tied their lives to the market, it is not just a part of their lives but has become their lives. It sounds simple but I believe that if the OP hypothesis happens, its severity will not be as small as we think.
It is not only the monetary loss, people create communities around the coins in which they invest and they believe in, so suddenly finding out that not only they have wasted their money but their time as well would be a very tough realization for most of them, and whenever this happens with a single coin we see many people complaining on the forum about it, if the whole market crashed and disappeared overnight then this would be many times worse, still while I think this is the fate of most coins, I am sure that bitcoin will be with us for many decades to come.