I wouldn't be so sure of it.
It's been forever I haven't been able to complete a fic, and yet not so long ago I managed to sit at the table often and long enough to write a novel-length book, and that was mostly because this time I intended to try and get it published.

Which might have made a little money (I wasn't counting on much) and get an actual IRL result, as opposed to putting a text online where you'll never know if anyone read it or not, apart from a few likes and comments once in a year (when I wrote fics, it was for small fandoms).

It wasn't fiction and I haven't found a publisher, but I did complete the book as I wanted it to be, in a publisheable form. That's a lot more than I ever did when I was writing fic.

There were other reasons involved in writing the book (I thought I had something to say about a topic I knew well that wasn't covered much in my country). But I would like if I said that "extra bucks from doing something I enjoy, as opposed to wasting the same time writing meta in dead fandoms" didn't play in.