I disagree. Better advice would be, if you want to be a journalist, "have a solid back-up plan" or "pursue it on the side". Even before the internet, it was a tough profession to be successful in. Now it is even tougher, but there are still individuals who manage to eek out lucrative and rewarding careers.

This advice applies to any profession that has significant excess supply vs demand. Athletes, photographers, artists, actors, musicians etc... Even if an individual never makes it big (and most don't) these activities can be rewarding hobbies as long as expectations are managed properly.