Because DL shouldered all the burden of imagineering the ride, and Pressler was cutting corners, they invested millions into something that they couldn't afford to finish.
I'm glad the Rocket Rods was a failure. My complaint wasn't that it was a bad ride (and it was), but that it was a thrill ride, and any thrill ride in that spot, unless it was the second coming of Jesus, I was not going to be happy with.
I prefer the People Mover because it was one of those long, calm attractions with little wait time where you can rest your feet and get a bit of shade. Disneyland needs more attractions like that. Well-rested happy guests tend to spend more.