Writing on Medium as a substitute for career at 30 is an irresponsible idea. 30 is an age there are lots of work opportunities. Try finding work at twice that age, nearly 60, and ageism shows its ugly head, almost impossible. At that stage income from Medium isn't a substitute, it is really nice and helpful. Along with a feeling of doing something positive about and increasing one's potential as a writer and earning. It's a responsible choice. Get rich quick scams unfortunately get into younger people's heads, especially if they are in a job they dislike. Good excuse to leave it but not the answer either. It's not easy earning money on Medium and leaving a job to do it is a bad choice, and isn't easy to get jobs either. Different if someone has no job and very limited changes of getting one due to age, etc.