First, lack of knowledge in cryptocurrency that's why they don't gain interest on investing in crypto. Second, even if they want to they are just too afraid of getting scam and being fooled by abusive people.
Before entering into this market, they must equip themselves with a new source of knowledge and take risks if anything happens. Most people are only interested in profit and are willing to give up the advice that their predecessors have. This is completely wrong because without the right advice you will be more likely to make mistakes.