You have that wrong.

A professional writer is not an amateur writer who never gave up.

A professional writer is a higly skilled writer who is usually talented. Writing to publication standard is as much a talent as it is a learnt skill.

On Medium, only 5% of writers earn over $100 pe rmonth, and that will always be so. That's because no content writing site ever pays more than that because the site has to make a profit for its shareholders.

As there are a lot of professional writers out of work due to the closure of a lot of print outlets, it's unlikely that those who are not highly skilled will ever reach a living wage on any of the writing sites. That is the sad, but horrible truth.

On the other hand, if you're a marketer and have something to sell, then content writing can bring you in a lot of money.