This would be helpful to evaluate Olsen’s hypothesis because (A) would be evidence bearing on whether horses were used mainly for food vs. mainly for some other purpose. If the proportion of horse bones that were butchered to those that were untouched were very high, that would suggest horses were mainly used for food (”butchered” in this context means cut up into pieces, which is evidence of use for food). But if the proportion of horse bones to untouched bones were very low, that would suggest horses were used for something besides food (which would support Olsen’s hypothesis).

It’s not clear the relative proportion of sheep and goats to horses has any bearing on Olsen’s hypothesis. If there were a lot of goats/sheep compared to horses, that doesn’t suggest either way whether horses were ridden by the Botai.

It’s not clear that the number of other tribes at the same time as the Botai compared to the number of modern hunting tribes in the same area is relevant. If there were a lot more/fewer tribes in the past, that doesn’t provide any reason to think horses were or were not ridden by the Botai.

It’s not clear that mortality patterns in other animals affect Olsen’s hypothesis. Other animals may have been used for food; that doesn’t suggest horses were or were not ridden.

It’s not clear that the proportion of human remains to horse remains is relevant. We know that some horse remains were found arranged in burial sites with human remains. What’s important is the fact the horse remains were arranged, not the number of human bones found with the horse bones.