I considered starting a quilting business when I retired. After researching the idea, I gave it up. Quilting is expensive and as others have said, few people are willing to pay the cost of materials involved in making one, much less paying you for labor. Quilts from China, made with slave labor, scant seams and cheap fabric are readily available for prices less than the price of making a quilt.
Another issue is whether you want to sell the quilts you enjoyed making or are willing to make what the client wants, in the pattern they prefer and the colors that match their bedroom (quilts on commission). And again, another issue is how much would you enjoy quilting after making quilts for sale. My personal experience with being a chef is that cooking is no longer relaxing and fun. It's just a job. I think many things are like that - you try doing something that you enjoy for money and ruin the joy of it. I like making memorial flower arrangements, but don't think I'd like it 5 days a week. And ... I don't want to ruin my enjoyment of making arrangements for my ancestors graves.
Some people make money by making small items for craft fairs to supplement retirement income. They make things like pencil pouches, phone bags, crayon bags, pot holders, etc. From what I've read, they do OK at it.
I would suggest you re-think your reason for asking the question. Are you ready to quit quilting? Do you want to supplement your income? Do you have too many quilts made and they are in the way? Do you think you are spending too much money on your hobby? Do you want some ammunition to make your husband shut up?
If you are serious about quilting for money, do your research. How much does it really cost you to make a quilt? How much time does it take? Do you have a longarm? What would it cost to rent space on a longarm, or have some one do that service for you? What kind of quilts sell? How do they get sold? What is the cost of selling one (website, renting space at craft shows, etsy, ebay, etc.).
I'm not poo-pooing your idea. I'm just saying that you need to think it through and figure out what is working for other people or how you can make a new idea work.
Personally, I plan to do quilting for Project Linus after I get all the family kids taken care of.
bkay