they have not understood in detail about bitcoin, crypto currency and everything related in it therefore they are not interested in this. others assume that this has a very big risk. so they are frightened to join
They're not interested because they are afraid to go out to thier comfort zone and try new things. This are the people cant fight the fear inside them and take a risk. Yet we cannot blame them , Not all people are like us that willing to loss or fail. And it is better to mind our own business and focus our goal toreach it.