It’s more that the West has just recently discovered Uma Musume. The show and the game it is based on has been enormously popular in Japan since its inception. I guess it just takes some time for a general audience to acclimate to the idea of racing horse girls.

As for the show itself, I haven’t watched it. However, I have seen it praised highly and seen some really, really well animated clips. They really put that gacha game money to use when they are animating this. @Endmaker@ani.social has had really great things to say about the story as well, and I have seen elsewhere that it is a great example of a sports anime (if that’s your thing).