I think the best evidence for Tesla doing poorly here (or maybe that LIDAR really is necessary) is precisely that they have all this data and still aren't doing as well as others. Tesla has a seriously absurd advantage here: they can observe millions of drivers and see when the human drivers do things differently than their self driving software would have, and capture the data from those events. They've had this advantage for many years, and yet, they still don't seem to be performing that much better (if at all) than competitors.

I agree with this concern. They collect a lot of data, sure, but they are also the only one who thinks that video is enough. It's a bold bet; intuitively, one would expect that video-only is good enough for gimmicks and fares worse when it comes to covering the millions of edge cases that still need to be addressed.

This is a curious point: How much data does Tesla actually collect? I can imagine users not being too happy if their car clogs the upload for hours every time you park it in your garage?

More than you think. There are sensors everywhere and pretty much all of them are regularly uploading telemetry to the cloud. This goes much further than self driving cars, the entire CAN bus is constantly synced with the cloud, all sensors, vibration, tire pressure, etc. All in the name of predictive maintenance and whatnot.