Some confiscated animals have been abused, others have not. Some owners give up the animals freely, others insist on partial reimbursement. Some rehabilitation sites keep some of these animals, but send most to sanctuaries. Also, like any other operation, they can't indefinitely spend more than they take in. Some just don't make it for various reasons.
Education is the key to compassion with effectiveness.
Animals that spend their lives serving man should not be discarded like so much surplus office furniture when they are no longer economically useful. Adoption fees are usually rather high because of the multiple expenses of food, diet supplements, medicines, veterinary care, and licensing fees. Joining with select others to pay a year's upkeep of an animal. Sponsorships are much more affordable and also make great class projects for a school. A non-designated gift of cash to a sanctuary offers them the most flexibility in using the resources where they are needed most.