Ideally, to make a story that everyone likes. Something big such as Naruto or Bleach but has meaning behind it such as...I won't say because not everyone agrees. I have two big stories like that that I would hope could be big but meaningful at the same time. I could always do them as an independent artist but for one; no money in that. I'm not that good to begin with. Also, a lot less people would find it.
So a step below ideal would be making a good living as a manga artist. It's technically possible but as risky as a 18yr old blonde moving to California with dreams of "becoming an actress." -- highly competitive industry with low high success rates (i.e. becoming really famous).
So a step further below that...I guess a hobby. If all else fails, I would try to fit in a convention here and there along with a crafts fair or farmers market and sell some stuff. All while having an actual, full-time job.
We all want to dream big and aim high, and at the same time, we also need to be realistic. If we want to aim that high, just be ready for failure and have backups.