A lot of tractors come standard with HST so it don't cost anything.
It costs something against the similar "equivalent" tractor with a gear trans.
Sure, there are model numbers that have HST bundled in the "base" price, just as there are different model numbers that have gear trans bundled.
I wouldn't expect a model with the letters "HST" in the model number to be available with a gear trans, but there is almost certainly a model with a "G" that has same/similar HP rating, lift capacity, same loader, tire/wheel size, etc and that model will be priced lower.
For the $AME DOLLAR$ you can usually get "more tractor" with a gear trans.
According to where you are on the price curve this might mean 5 or 10 HP, it might mean bigger implements, it might mean a Cat 2 instead of a Cat 1, or a Cat 1 instead of a Cat 0.
Heck, it might even mean more capacity to do the same tasks more SAFELY.
Anyway, I think the next big argument here will be about black vs other colored tires - a FAR more important issue.