I have several thoughts on this topic.
1. As others have stated, turning my hobby into a business would take the pleasure out of it. It would become a matter of 'have to' instead of 'want to'.
2. I was planning when I retired in a few years to buy a long arm quilting machine. I would first practice on my quilts (I must have about 15 tops to quilt). Then I could take in side jobs if I wanted to but at that point, it would just be for some extra money. It would not be money I needed to live on.
3. In my area, there are so many long arm quilters, I don't think anyone can turn it into a full time, profitable business.
4. People don't want to pay the price for any handcrafted items. A few years ago I was making some fingerless mitts, not for sale, but for myself and my family. A co-worker commissioned me to make some for her. It took me 6 hours per mitt. I charged $25 for both mitts. A 2nd co-worker said that was too much, that I should charge cost of materials + 10%. There was no way I was going to sell those mitts for under $10.00. Even at $25, my hourly rate of $1.67. The public in general does not want to pay the appropriate hourly rate for handcrafted items. I have seen quilts with price tags of over $1000 on them. They weren't overly great quilts either. People aren't going to pay that price for a quilt when they can go to Sears or some other store and pay $50-$100.