Cost is the ultimate factor. This is a guess, but all 8 cameras on a Tesla is the same cost of a single radar unit ($5000 I read).
LiDAR is on order of $50,000 for full system today (suite of 5 LiDAR scanners).
Respectfully, I think all of these cost numbers are way, way off - on the way-high side. Unless perhaps my browser refuses to render decimal points
I would believe an automotive radar unit, as used for collision-avoidance braking and adaptive cruise control in many cars (including radar-eqiipped Teslas) costs something like $50, perhaps $100 but not more in volume. This is not talking about possible future deployment of high-resolution millimeter-wave radar for external detection - though still that would not be in the several thousand dollar range if it's going to get deployed.
Tesla's 8-camera suite? Including housings, harnesses. heaters? My rough guess is a few hundred at most. $1k IMO sounds unreasonably high for what they do presently and for what could possibly be contemplated to go in a $25,000 Tesla upcoming. So the $5000 figure is, I'd say, 10x to 50x too high. (But on another topic, I'd be all for them to splurge just a little for more and higher-quality ones.)
Cost of Lidar is a bit more complex topic. The figures of tens of thousands of dollars are a holdover from early 360-degree electromechanical units built in limited volumes for prototyping, research and mission-critical cost-insensitive applications. Not for recently-designed, high-volume-targeted and primarily forward-facing Lidar arrays that you're likely to see pretty soon in production cars. I'll venture a guess that the latter might be several hundred dollars, maybe even higher at the moment but if so, with a supplier promise and a credible business plan to demonstrate a downward cost progression fairly quickly into the low hundreds. Otherwise they would not be seriously considered for consumer-vehicle ADAS use at all.
And by the way, these estimates do not imply the Elon was wrong, lying or misinformed when he made his decision and pronouncements about Lidar for FSD. Tesla had to make decisions in the 2016-2017 design time-frame to adopt and finalize a hardware suite that would be reasonable for cars with a planned highly-capable system to hit volume manufacturing starting in 2018. I'm pretty sure there was nothing (Lidar) available at any reasonable cost or production-readiness at that time. Given that, there
was no realistic path for a Lidar-dependent FSD platform that could have achieved Elon's/Tesla's goal that the upcoming product generation (the cars we're driving right now) would be capable of autonomous driving. It is a related but
different argument regarding whether Elon was mistaken, then and now, about Tesla's ability to achieve the goals of FSD without Lidar.