After you have a license of you own, I would consider talking with the right person (high enough up, but also approachable) about your future with the company. You may be offered the opportunity to grow within the company and gain valuable experience, or you may be shown the door, who knows. But it's worth it to find out.
I know several contractors that started working for a big contractor while they got their license and gained experience. When they were ready to branch out they had a good relationship with the big company and a significant portion of their workload came to them through that big company. It would come either as a referral because the job was to small for the big company, or they would sub-contract out to them. Being your own contractor means you have all your insurance and bonds, they don't have to cover any of that. They can set a price and reasonably expect that to be what they pay.
If it turns out that you're not good at the business side of things, they may take you back. Shoot, if they see that you're motivated they might make it worth it to stay. But I'd bet that if you don't talk to them about it and just leave, they probably won't give you the time of day.