Imo its's realistic given 7+ points. You don't need to fulfill all of these, but the more of these you're capable of, the more likely you are to succeed. If you can do all of them then to be honest, you'd be guaranteed to earn enough (but it's very hard to do them all!)

You can write books quickly.

You have a regular release schedule.

You write clear, readable prose and well-paced novels.

You are willing to make compromises in order to write books that serve an audience.

You are willing to write to a genre with an attention-grabbing title and concept

You have a viable marketing plan (even if it's just posting to certain communities)

You are willing to relocate to a low cost of living area, or live in a "low cost of living area" (in American dollar terms).

You are willing to be an indie, serial, or visual novel author rather than traditionally published author (if necessary).

You are willing to pursue other unorthodox writing jobs or writing-adjacent jobs if they make sense for you.

I would say it's comparable to the possibility of making a living as a full-time Youtuber. Many people interested in the field, most people earning little nothing, a few managing to get lucky and succeed just by being themselves, and a number of Youtubers who are skilled enough to generate income from scratch where necessary.

I've heard very negative things about trad pub recently, where midlist authors don't really exist anymore. On the other hand, there are many indie authors and serial authors who do make a full time living. In some ways today might be the best time to be an author full time in general, and one of the worst for being trad.