It's already been explained, but I'll explain it again. The PeopleMover at Disneyland closed in 1995, and a thrill ride called the Rocket Rods (one of my favorite rides as a child...it was almost like riding an outdoor version of Space Mountain) replaced the attraction in 1998. These were the times when Disneyland was in shambles and run by poor management. As already stated, the turns weren't banked, and the ride had to slow down first whenever a turn came. Another problem was the tracks. The tracks weren't made for a fast ride, and Rocket Rods destroyed them, pretty much. Rocket Rods closed in 2000 for a "refurb", and it never came back. Now the tracks just sit there.
PeopleMover:
Rocket Rods:
Here's the sign, reading it would be back in 2001:
The rocket on top of the "stage" is a remnant of the old Rocket Jets, when they used to sit up top and not on the ground: