I'm seeing a few recurring reasons as to why people don't invest in bitcoin, which makes sense when you look at it from an outside perspective. I believe that the combination of trust issues/perceived unreliability of bitcoin is what deters people from investing. If more people looked into cryptocurrencies and the reasons as to why they were created, more people would be inclined to invest.
Will a world where everyone switches over to crypto happen any time soon? Probably not. Is it possible that sometime in the near future everyone will own a share of crypto similarly to how everyone is currently invested in the stock market? Hopefully.