I think everyone's explanation is partly correct, but you've left out maybe the BIGGEST factor why horses are taken off the track because of "injuries"- money made in the breeding shed. So, sure, they will say a horse is injured, and I'm sure most of the time it's true, but after the colt has run some good races, they just figure it's easier to shut him down, not risk diminishing the stud fees with any losses, or any more serious injuries, and go from there (as opposed to letting him heal and run some more). Back in the days of "the Biscuit," Whirlaway, and others, the owners and trainers really felt they owed it to an adoring public to race these beloved horses so their fans could see them and cheer for them- today, do you think they still feel that same sense of responsibility? No way. A couple of big wins, and let's syndicate the horse for millions- it's sad and it's our loss.
