We are moving next month to our new place, and we will have 5 stalls there, which I am excited about. I like having the option to put them up in the barn during periods of too much rain, bad weather, rescues that need more weight, and so we can get a stallion, and for the Arab mare we have bred next year when she foals.
That all said, clearly horses should be able to be turned out. Imagine what people would think if crated your dog or cat all day and night, year after year, not even letting them out to use the bathroom but every now and again. You'd never be approved to adopt from a pet rescue, let me assure you. I do not know why it became okay to stall horses 23 hours of the day, but in many cases, it is owner convenience only. . . cases where there is no room, but people would like to have a horse, but they can only get out a few times a week to get the horse out of the stall. . . hmmm, I don't think it is ideal at all - but I know it is rarely from anything but the best of intentions.