Lack of knowledge + traumatic experience = fear of investing in bitcoin
People that are avoiding bitcoin because they have no interest to deal with it. Ignorance makes them fear to invest in bitcoin. Since bitcoin is broadcasted in television that it is a scam, people are fear to invest. That is why, we, pioneers of cryptocurrency must share also this knowledge that we have in our society (friends, colleagues and families). So that, we can help other people as well as bitcoin community to become knowledgeable in terms of investing and using of bitcoin as currency.
This basically summarizes why some people avoid Bitcoin in the first place. Lack of confidence is the main issue surrounding Bitcoin as people believe a decentralized currency not backed by a reputable authority is a scam or Ponzi scheme. If they knew how Bitcoin truly works, they wouldn't believe such misconception. We may try our best in spreading the word about Bitcoin as much as we can. But at the end of the day, the majority will use Fiat due to its widespread acceptance by businesses and merchants worldwide. At least, Bitcoin will have its loyal supporters that will keep the revolution alive for many generations.
Nonetheless, mainstream governments, central banks, and mainstream media have done their duty to try to harm Bitcoin's reputation in the mainstream world. It's no wonder why most people haven't fully adopted Bitcoin for their own benefit. Rest assured, that as the mainstream economy collapses, more people will resort to Bitcoin as a store of value. Ultimately, Bitcoin will become the next generation of Gold as it becomes scarcer with every halving event. The next 4 years will become quite interesting for Bitcoin as it grows in mainstream adoption due to the latest reduction in its block reward. The closer Bitcoin gets to the max supply of 21 million coins, the more demand it'll experience on the market. While Fiat will still exist in the future, Bitcoin will become a force to be reckoned with as it remains truly unstoppable. Just my thoughts