You didn't ask a question, you made a statement, and an incorrect one at that. I felt the need to admonish it.
Major soundness issues would be attributed to horses who have chronic shins, ankles, knees, etc.
First Sam was a very big and heavy horse when he first started out.
After breaking his maiden at CD in July, he then ran in an allowance race and the Hopeful in about a 20 day span. He then won the Champagne and ran back in the BC only 3 weeks later suffering his first loss. He ran only three times at age 3, but those starts were fairly close together in a time period. He never missed a scheduled start, not one, and his only layoff ever was his last one. The broken rib was obviously a freak thing, and breeders don't worry about horses who had broken ribs, lol.
His last start was with teh broken rib and very often a horse running an entire race with a problem will cause himself damage because hes not running straight and true, he or she is running in a very choppy manner to try and "get away from" or compensate for the pain.
Horses often emerge from these races with a variety of problems, many of them muscular(which was the case here, no fractures or chips) from running in such an awkward manner.
By the time they got a timetable on how long it would take to straighten him out, they realized that it was impossible to have him ready to run in any races of consequence at the end of the year. So they retired him. Contrary to popular belief there wasn't any pressure on the owners to retire him. They did not sell the horse before the Blue Grass, only 25% of the breeding rights. They retained the other 75% to sell at a later date or keep a percentage of as they saw fit. Claiborne was never calling the shots on this horse, the owners were.