People have given up their day jobs and has moved full-time into cryptocurrency related earnings and career. These are people with high investment as well as after learning about the market. A common man too can make something out of cryptocurrency, but in between should not look for big profits ending into a big loss. Most of them relying on Bitcoin and other cryptocurrencies keep on practicing trading which is the base where the money flow of cryptocurrencies were found.
Saying that relying on bitcoin isn't possible is not a informed sentence (not about you, but about OP), basically, as you do say, many people have moved full time into cryptocurrency related careers, and that speaks volumes of the potential cryptocurrency brings into the table. Not everyone in the area trades either, I know a fair share of people who don't trade for example but earn in bitcoin exclusively for example.