It is not just one thing preventing them from investing, my friends all have different reasons, some is because of fear of being scammed after being victims of thieves online before, they have not been able to overcome that fear and move forward. I have another who knows about bitcoins but say she does not have enough money to invest for her basic needs so does not have to invest. I met someone who their own barrier is not money or fear of being scammed, but just that they do no believe bitcoin will do well for investment so they have invested in other things. Another person is  lack of enough knowledge sufficient to invest. Many people have their reasons, but it takes personal effort to overcome the different barriers.