what happens to the birds or other animals that no one buys after 10 months or more?

there was this one bird that was at my local petco for almost a year. He is as initially very expensive. like $1500 or so. his price dropped over the months. I go in today and the employee says he was bought by a man who adopted many of the birds when they get super discounted.

Just wondering if animals will sit at Petco indefinitely until purchased... also if this man exists you think hes running like a bird sanctuary or flipping the birds for profit?