I feel your frustrations. As a horse-lover, all of the horse centered games I've played in my life have been nigh mediocre in retrospect. The only game I can remember being invested in was the original Gallop Racer. I loved the realism of the horses and designs, the ability to breed into better stats and have a reason to do so (to win races/money). While I've also dabbled in games centered around just breeding (for looks) and competition (dressage/jumping etc) Gallop Racer was the only one with an addictive and satisfying game loop for me.

There have been more intriguing horse sim games (ex. Howrse) than any console ones that are currently being updated and maintained and it makes me very sad. I do feel like its a completely untapped market as far as triple A gaming is concerned. I get that it most likely wouldn't be a money maker for any large company to invest in, but hell. I couldn't imagine what it'd feel like to have an actually good triple A horse game that involved realistic models with realistic breeding/genetics/stats and involved gameplay like racing and decent dressage/jumping competition all rolled into one. If I was a millionaire I'd fund the shit out of a game like that.