Elon also tweeted a few days ago about how roads are made for vision, so lidar is not needed. He does not seem to understand the purpose of lidar.
I would bet rather a lot of money that not only does Elon understand the purpose of LIDAR, but that after a decade or so of hiring and working with some of the world's top experts in autonomous vehicle development, he probably has a much better handle on things like redundancy and sensor fusion and whatnot than any of us do.
My personal theory-- which is worth every penny you paid for it-- is that Elon likes to cut costs. Chrome trim to black? It's cheaper. Elimination of things like turn signal stalks and other physical controls? It's cheaper. My 2013 Model S had a smorgasbord of options to choose from-- remember when the power rear hatch and fancy sound system were options?-- while my 2023 Model S LR had paint color, interior color, and wheels as choices, and that's it. Because it's cheaper to build cars when you have fewer options. People may gripe about the passenger seat in their Model 3 not having power lumbar support, but Tesla may be the only company in the world making a profit selling EVs. Ford, GM, etc. sure aren't. ANYWAY...
It's also cheaper not to have LIDAR and radar. I dunno if Elon walked into the FSD engineering room one days and said "We're doing it all with just cameras", then turned around and walked out, or whether he had weeks of intense technical discussions on whether a camera-only system was feasible, because if it was, they could save $XX per car. Maybe it wasn't even his idea. We'll never know.
As we know, Elon will go for the snappy, off-the-cuff sound bite like "roads are designed for vision", even if it doesn't really make that much sense in context. Remember, this is the same guy who said the new Roadster (hey, does anyone remember the new Roadster?) would be able to physically fly.
Will Tesla actually manage to deploy an FSD system that's vision-only? I dunno. I'd think that if 11.4.7, which my car just got, had been described a couple of years ago as a vision-only system, it would have been widely decried as "Impossible!", yet here we are. Years behind Elon's ever-evolving due dates for "true" FSD, granted, but in the 18+ months I've had it, it's been getting incrementally better almost every release. What we have now would have considered a technological miracle two years ago, weird edge cases notwithstanding. I use it every day and have a pretty good mental map of its capabilities, and when I should expect to intervene or simply turn it off and drive myself. I've driven in heavy city traffic and cross-country with FSD, and I'm...optimistic about its future. Even without LIDAR.