I know probably three dozen authors.
$500k every two years seems great for a job that so many people romanticize, but the money goes fast. The writing is the easy part. Self promotion becomes a full-time job, and you do the writing in your off hours.
Also, you don’t get to take all that money home. Your agent gets 15%, but you’ll never get published at all without one. And there is an unspoken rule that you must put a certain fraction of your advance into marketing yourself, the proportion depending on genre and level. Most authors at the $500k level (“major deal”) have to retain publicists and live in New York to sustain it. The publisher might give you one hour per quarter with a publicist if you’re really lucky. If you want favors called in and arms twisted to get your book coverage, you have to pay for that on your own.
The best way to be a writer is honestly to get a 9-5 you don’t hate and that stays 9-5, and then self-publish and accept the likelihood of obscurity. The book world is toxic and the proportion of actual smart people isn’t zero but it’s no higher than you’d find in a decent high school.
If you go trad and you genre-maxx, you’ll get typecast to one niche and be treated like shit the moment the house no longer sees you as a reliable 7-figure line item. If you try to go literary, you’re forced to write within the narrow confines of a social class and format you probably won’t enjoy for the next forty years.