Yes, but developing a better horse has a low likelihood of success and a relatively long time horizon. There are some arms race dynamics here in that as long as no one else is trying to develop a better horse, you probably are better off just not trying to either.

> what if there's an even better horse out there

Doesn't matter, such things threaten the horse investor lock in economics.

Many years past, an early bit of software from my student days was a side project making an easy to use database system for a horse stud farm, high status stallions being put to mares with the feed, vet visits, results, etc. all logged.

Horse racing is pretty much all about pedigree - without the lineage horses are considered valueless by the industry - super fast back country waler crosses might be acceptable for a four mile charge across open ground onto machine gun nests .. but w/out that pedigree <shrug> no Lord or up and coming billionaire is going to syndicate that horse for racing.

I imagine Polo to be much the same, in the rich set. Probably more open and accepting out on the steppes knocking about the heads of the vanquished.

There’s commodities and then R&D. Ignoring every other moral consideration, this horse cloning has turned a biological asset into a (relative)commodity, and if people were looking for better horses they’d stick to the randomized mutation of regular breeding which has that built in as a feature.

This isn’t even the only instance of this technique. You can look at the Argentinian president Milei who hired a company to provide him with consistent advisors in the form of cloned dogs he talks with through a mystic[1]

[1] https://en.wikipedia.org/wiki/Conan_(Javier_Milei%27s_dog)