Iff cameras only works. With threshold for "works" beig set by Waymo, since a Robotaxi that's would have been acceptable per se may not be if it's statistically less safe compared to an existing solution.
Waymo also sets the timeline. If cameras only would work, but Waymo scales before it does, Tesla may be forced by regulators to integrate radars and lidars. This nukes their cost advantage, at least in part, though Tesla maintains its manufacturing lead and vertical integration.)
Tesla has a good hand. But Rivian's play makes sense. If cameras only fails, they win on licensing and a temporary monopoly. If cameras only work, they are a less-threatening partner for other car companies than Waymo.