I have been asked the same question many times. I am currently an avid hobby quilter, but will make it a retirement job (in 15 years!), I hope.
I do have 1 quilt I'm working on for a "customer". A fellow I work with wanted a t-shirt quilt made. I told him I'd do it for a combined payment of cash and his fantastic BBQ sauce! I'm not done with it yet as he doesn't have a timeframe. But I got a jar of sauce as a down payment!
I have another lady at work that would like me to custom make the entire quilt for her. I told her I would discuss it with her, but she can't have a strict timeframe as I do have a "day job"! I also explained the cost of the quality materials, and my time. She understands and fully expects an "heirloom", not just a Target or WalMart quilt.
I think the mindset of the customer is key to choosing who you want to make a quilt for, if you choose to!