I think it's all about the timeline. Tesla gambled on cameras before AI models became usable (the company most certainly committed itself to the camera sensors a few years before it became public). By the time automated driving models became usable, Tesla had tons of camera data to capitalize on, but presumably not the corresponding radar data (or not in a consistent manner), so rebuilding a multi-sensor dataset for AI training was probably not very appealing in terms of cost and time to market.

Back when Elon made avoiding LiDAR a core part of his professional personality, it was fairly expensive. But as any tech genius can tell ya, component prices drop rapidly for electronics.

Now, radar is dirty cheap. Everything has radar. Radar was removed from Teslas. A radar sensor for my truck is $75, probably much less at scale orders.

LiDAR sensors cost anywhere from $500-$1,500 for a vehicle of this type, near as I can tell (this type being Level 2 autonomy rather than something like a Waymo. A well-kitted out self-driving vehicle has 4 LiDAR sensors).

Here is the LiDAR module currently used on the Mercedes S-Class, it's $400 used: https://www.ebay.com/itm/285816360464

It's a hideously small cost-savings in 2025 for a luxury vehicle like a Tesla. Any rational company would've reversed course after the first stationary-object-strike fatality. Tesla is not a rational company.