Honestly TOO much blood?

Is there an honest pro or semi-pro rider out there who would actually admit to having a horse with a pedigree to die for but it is just too difficult to ride or has such bad charachter its impossible to progress or its just off its head and is so stressed by everything that it does not concentrate.

I have been working proffessionally with serious sport horses for a long time now and I am looking at the breeding of future sport horses and in seeing the choices of breeders, I see potentially big profits from foal sales but potential disaster for the horses when it comes to being ridden!!!!

Do any others share my views on the high blood horses for top sports?