I posted to give an example of what can happen when you use a TB mare bred to race, not for sport. How many times and at what expense was I to repeat a breeding that went back and pulled up the Mr. Prospector/ND genes of the grandsire that made the end product look like a QH? How many generations would it take to breed that genetic dice roll out? Even if it did not show up right away, what about the F2 generation? Holstein added the TB years ago for refinement and patiently worked with what it did and did not do for them.
I gave one example because it was mine to give, my story. There are others but those stories are not mine to relate.
Since the OP started with, “the TB kills the jump,” one would assume high level GP jumping. Eventers and steeplechasers exhibit other characteristics including speed and jump in that format. But I would also remind that Connemara crosses have had success there as well as other breeds. I remember some Appaloosa’s that tore the courses up at a regional level. So non-TB success stories are there just as well and just as frequently as TB GP jumpers.
TB’s I admire for the handyman they are, racing, polo, etc. But jump specialists they are not and I think that is where the original question lies.
If you look for consistent product, it would not be a TB mare base because they are only bred for consistent results on the race track.
One could also say that TB’s are nothing more than local mares bred to very select Arabian/Barb/Turk stallions, albeit a bit further back. And it’s been postulated that the TB needs an infusion of something, but it’s a closed book. If the WB people cannot find the right kind of TB anymore, it’s because that closed book and sales/ baby talent-oriented thinking has created what it has.
But I’ve been there, done that, bought the T-shirt, and wore it out, and I’d rather people know the other side of the TB argument in WB breeding, because it just isn’t that easy to use the TB mare base in this country and get the same results. People really, really need to know that the TB isn’t the be-all/end-all animal, unless it’s just the right one. Getting hard to find that gem any more. Study how, who, and on what mares the TB’s of the past were used in Holstein. Ask the people knowledgeable about the failures, culling the results, and what to cross on next. This thread could be a gold mine of information. Whether you want to buy into it or not is up to you. I would lament the loss of a “nugget” of wisdom just because some disagree.