People who has a day job usually makes the bitcoin world as their side line. They wanted to have multiple sources of income. People who are doing bitcoin in full time are mostly people who are people who basically can't get a job for some reasons. Although not everyone who's full time on bitcoin are uneducated, there are some people that chose to make Bitcoin as their day job. Maybe because they are earning much more in bitcoins and they want to focus on it, and they just see their previous day job as a disturbance to their bitcoin journey.
Those people who are already on trading like forex and stocks trading can easily adopt on bitcoin. They can make bitcoin their primary source of income because they already know the ins and outs of trading. They can make a lot of profit from bitcoin whether the price is going down or up. But those who have an office jobs will have a harder time switching from office to bitcoin. They are used to having a fixed income and the fluctuating price of bitcoin discourages them.
People who trade on forex also have jobs, you know. I don't think you can make a living solely based on that.