Ridergirl99, I came out of a top program. Some of the horses are servicably sound ie kind of lame sometimes, because that’s why some of them were donated. Many of them were still super educational and useful, but had good days and bad. I don’t think it was a bad life for them at all. Except the ones who really hated being lessons horses, but they usually didn’t last too long and were returned or resold to private homes.
Retirement also varied, some were sold or adopted to students/former students. Many did work until they were put down. A handful were returned to owners, but yes, this pretty much depended on the former owner’s desires.
I do know another school I taught at where riding was a club sport rather than a team, it was much more hit or miss. Some superb donated horses (who could not be resold as per contract), but lots the horses came from buying and selling at local auctions.
In my time spent around various programs, i never witnessed any abuse or neglect. Yep, you might have a lame horse or a ribby horse, but some horses are just harder to manage than others.