I think those people who are not joining bitcoin ,are the people who believe that bitcoin is worthless, but to the people who really invest on bitcoin and understand the concept of bitcoin and cryptocurrency would always believe the worth of bitcoin in the coin market cap and the entire digital business.
There are several groups of people that think Bitcoin is worthless. The first one is the guys who earn enough (or get enough) not even to care about crypto. The second one is skeptics, who simply do not believe in BTC.