Very well put, Sys. Excellent examples of purebreeds with health issues are...Dalmations having blindness, German Shepherds with bad hips (my own family had to put one down after having him only a few days because of the suffering from this affliction...very sad), and Bulldogs with their breathing issues to name just a few.
My family has for the most part been a 'mutt' family and have had a long history of loveable pets with unique personalities. My wife and I currently have a Mini Schnauzer which my wife had before we married and though he is pure, he is as loveable as a mutt. My case being that there are issues with a lot of pure breeds, not that they are unworthy as pets. Dogs really do make good friends to human kind no matter which breed.