I have had my long arm machine for almost a year now. I waited 6 months before soliciting paying customers. I do mostly pantographs and an occassional custom quilt (outlining, patterns and/or meandering).
I started with some women I met through my church group. Every social group I belong to has potential customers in it.
Yes, there are a lot of quilters in my area and several longarmers. Most women who can will finish their own quilts, but there are those who either are not able to finish their own quilts or don't want to. I'm sure economics plays a part in whether or not quilters want to hire a LAQ.
Bottom line: Don't go into debt expecting to pay for the equipment with machine quilting business. If you can relax and enjoy the time it takes to build a business and establish customers, you are better off. It does take time!