It is very much possible to live of crypto for as long as there is crypto. Honestly you have to know to withdraw some of the gains you make before a market downfall. So if you play it smart it is definitely doable.
The point is how to play it and to know how it is with the knowledge that we have learned as much as possible, so all that can be done as long as we have enough knowledge to carry it out, because every job requires knowledge of each and to have knowledge is certainly not an easy matter for each person.