I am not totally sure about national currencies but threat in job is absolutely possible to happen. Actually it is happening right now in the current scenario. I've known a lot of people who left their regular job coz they are already earning so much money here compare to how much they earned on their job.
Expecting cryptocurrency as national currency is not good because the government will never leave their national currency just for crypto. Always think logical when government has control over it. But as a job i also agree that many people already resigned from their regular job and do crypto job.