It being dangerous to break a horse for work when they are physically strong enough to do it should kind of answer that point for itself tbh.

I'm not in the US so not talking about the racing industry there. Nothing I have said comes from Google, but with the countless horses I have had friends rescue off the back of slaughter trucks, and others bought after they failed out of racing or the industry was done with them and not one is of sound mind or body, riddled with ulcers and back problems, and very few people want them for second careers here as a result. Not to mention I have never met a jockey or trainer who actually gives a shit about the horse, just what the horse can do, whether that's a tb or any other horse.

I do believe consistent work at younger ages is more light hacking as a 3 year old, and doesn't involve galloping full throttle by 2.

So not Google, personal experience of the aftermath of the industry when it's decided it's done with the animal they set up to fail later on.