I had a QH that was determined to not be sound for what I wanted to do with her. I bought a new horse and gave her away.
Why not? I had no use for her and she is THRILLED that she now stands in a pasture stuffing her face all day except for a 30min nose to butt trail ride with a small kid on her.
Trail ride facility was overjoyed to get a horse that is completely bombproof on trails, loves small kids and gets fat on air. They didn't need a horse that was sound at the canter, heck they don't even trot her!