All of my friends who have invested in bitcoin can attest to the fact that it is an exploration of one's self. Many of these gentlemen from many disciplines have come to understand who they are by their commitment to their relationship with money, their level of risk tolerance, and their capacity to maintain discipline in the face of uncertainty. In the face of the market and their personal life, they have evolved into a sort of stoic mentality. And those who backed off during the bull run did so for the same reasons—self-discovery. They assessed their possibilities of success in this high-risk environment and decided it wasn't for them, so they stayed with real estate investments, which are generally low risk.
Bitcoin and cryptocurrency investments aren't for everyone and not everyone can maintain their assets and investments, so it is better for anyone to first evaluate the situation, study the industry, and then check their own capabilities to see if they think they can manage everything successfully if they think they can, they should go ahead with it, but if they think they can't do it and it is not for them, they should simply choose something else.
Your friends probably thought Bitcoin or cryptocurrencies are not for them and they chose another stream to invest their money which might be seen as a bad decision by many because people believe in Bitcoin but it's obviously the best decision for them since it might save them from big losses that they could incur for themselves.