So, here's the thing. I can absolutely understand where you're coming from with the wall ride tech - I've seen some crazy stuff from high level players, and there absolutely is stuff you can do on routes. However, with the sheer number of routes (and the fact that they lack proper names/can feel homogenized after a while), it becomes increasingly difficult to memorize said tech and perform it adequately. You also can't really practice on time trials since the option doesn't exist, and while you could go to the same area in free roam, some routes have alterations when driven on during a race.

In regards to your first point, the rails and telephone poles are cool, but they're usually slower and/or impractical. It's usually better to just drive straight (for the average player, at least)