Faced with no robot T-Rex mount in Horizon, I would rather walk

Behind the scenes I have been chipping away at Horizon Forbidden West on the PS5, a game I would characterize as good, lots of fun, very pretty. (Sidebar: having recently conducted an inventory of all my posessions for international shipping purposes, it appears the PS5 is literally the most valuable thing I own. I am 32 years old). I’m not very good at it, to be honest, so recently knocked it down to easy difficulty in order to stomp on robot heads with greater efficiency. Good ol’ Aloy.

Anyway, now that I have awakened a sort of mother-surrogate AI and started the actual business of saving the world, I cannot help but ask the key question: why can I quiet not ride into battle atop a massive great robot T-Rex?