Well in my opinion there are cuddle quilts, bed quilts, wall art. I love that there is so much variety.
As for shows if you don't like the rules maybe volunteer and help the rules evolve. My guild show is this weekend. There are several divisions of the quilts. There are categories for one-person quilt which is one person doing all the piecing, quilting and then there are two-person quilts. There are artisan or master entries so if you have been a previous winner or been paid for your work then you are automatically competing in the master division. There is also a category for first time entry. There are awards for merit hand quilting, and merit machine quilting. there is a category for digitized (embroidery) designs. So probably most of these divisions and categories came about because people discussed the issues and made decisions.
One last point... I love to see the quilts hanging. This is something so inspiring and fun. I like seeing one of mine hanging. I love that the guild show promotes our art.