There would be several potential benefits in canceling:
1) Tesla does not have a good reputation for delivering features in a complete and timely manner. If it takes years for Tesla Vision to reach feature parity with Ultrasonic equipped 2022 models then I will not have to live without these important features in the interim. During an extended period without ultrasonics there's a high probability of damaging the the car and tesla would not compensate for such avoidable damage of course. I can instead wait until either
A) Tesla fully implements tesla vision, or
B) Tesla gives up on tesla vision and returns back to ultrasonics, or
C) My RIVIAN R1S gets delivered in 2024
2) Get additional features that are not available yet such as:
A) Hardware 4.0 (better FSD, better cameras)
B) Matrix headlights
C) 4680 batteries
3) There may be many people doing the same calculus that I am doing and deciding that they don't want worse features for the same price. Delivery backlog seems to be shrinking precipitously (my X was originally due Feb-Apr 2023). The reduced customer demand may force tesla to start cutting prices or adding features or both