There’s no way this is true in 5-10 years. I’m in a $20/person/hour campaign now. A future celebrity/influencer/streamer/professional improv comedian GM could easily be pulling in 6 or 7 figures.
I guess I don't want to say you cannot make a living off being a paid DM, but you will have to be in the top percentiles to justify your price doing so and compete in a shallow market. Everyone else is on borrowed time until the player:dm balance naturally normalizes, and speaking as a DM myself I do my utmost to convince others to give it a shot because it's an incredibly enjoyable and rewarding experience.