The shows I do here tend to run at about $100 for a 10 wide x 8 deep space. But two of my shows is $100 for a 10 x 5 ft space and I always pay an extra $10 for electric. But I have fine-tuned my shows to where I only do the best ones where I sell the most. My most expensive booth is $200, but it is 20 ft wide and is a 4 day show.
When I first started doing that 4 day show, I had a 10x10 space. It was nice, I did well, but after a couple years there the person next to me did not show up and the director asked me to spread out into 2 spaces. Luckily I had some extra tables in the truck. I had my most fantastic show and sales ever that weekend. We decided it was the extra real estate that helped me. So, maybe you want to consider spreading out into 2 spaces.
I've noticed that sales have gone down at most shows over the past couple years, but not by so much that I would stop doing them. I did find that creating some new items that could be sold at a profit for $10 or less is a great help to increasing total profit. I always try to have a few new items each year to keep people interested in coming back to my booth. I get a lot of repeat customers.
I don't think you are crazy to continue to do shows if you like to do shows. But if I were you, I'd think about extending my show area. I'm lucky that my daughter lives in the southern part of the state, so I do shows down there, as well as in my own area. So if you could find a way to try some well known shows out of your local area, it might help. You never know what is going to happen at a show and what it will lead to. I once was commissioned to do a large quilt that I was able to charge $1,000 for and all because I was sitting at a show with my little 20 inch quilts on my table. Shows are fun.