Well, Big Brown was actually wearing special shoes that weigh a bit more than normal ones, because of his foot problems, so I think that in the upper levels of horse racing, concern for the animal does outweigh getting them to the finish line at any cost. You could argue that the concern is really for their value as studs/broodmares, but they have to have good track records to be worth much money in the breeding barn, and a horse who breaks down early in its career will be a bit suspect as breeding stock.

When you get away from the top level of racing, though, I agree it can be pretty bad. The good news is that in the aftermath of Barbaro, the racing industry got a good solid wakeup call to improve conditions at all levels, and a lot of work has been done. The growing popularity of synthetic tracks (more spongey and rubbery and hence more giving underfoot) is one product of that work.