Dr Johnson said that no man but a blockhead ever wrote, except for money. But he was wrong. Only a blockhead would choose writing as a way to make money. Even the simplest cost/benefit analysis shows that a successful published author would be better off employing his talents in the service of Mammon if money is the main objective.
Most writers earn a pittance. Too much of their time is devoted to activities other than writing. Months spent trying to get an agent or a publisher. When their book is finally published, publicising it. Better to have a decent job and publish for nothing on the web.
To be fair, he also said a man may write at any time, if he will set himself doggedly to it.
And that's the best advice anyone can give.