It’s interesting and rather funny how our culture tends to measure success. By most accounts when and if you quit your day job, you’ve succeeded. In fact, it’s so unexpected and impressive that there are no other qualifications. Your world could be falling down around you - your relationships on the brink of failure, your finances a complete mess, your artwork unappealing, etc., and as long as you're making art without a day job, you’ve “made it.”
In terms of my own personal success, taking that leap did, in fact, make me feel as though I had “made it.” It was empowering to feel as though I was a part of something greater - a long history of artists who spent their days and nights consumed completely with their art. I set out to achieve something and was willing to risk everything in order to achieve it.