This is a common problem, and one I could rant about easily if I let myself. My only advise is to keep trying. Now that you can recognize the signs of flaking out, you can deal with them faster. Eventually, you'll find people that are loyal. I burnt through about 10-15 artists before I ended up with a nice core group of people. I'd also suggest searching away from the AGS community. The folks here are mostly hobbyists, so hardcore loyalty is hard to find here. Also, if you can pay a little bit by-the-job (i.e., per background or animation or whatever) it gives you a little bit more clout.