I think it's possible to make crypto a full time job but only if you want to become a professional trader. Mining is also suitable for this purpose but in this case you need serious investments to create your crypto farm. As for bounty and investments in ICOs, I don't think it's a good idea to quit your job.
There are many jobs that you can get in cryptoworld not just trading, but seeing the fluctuating price changes will certainly make your income uncertain, do you dare to depend on non-steady income? that's your choice. but in my opinion, as long as crypto income meets your needs, whatever the job, why not?