This is not really accurate. Our brains do the distance estimation, and they use all kinds of tricks and contextual clues to do it, not just parallax (~2.5 inch parallax for objects more than ~100ft away isn't all that helpful). And this is the whole problem with vision-only autonomous driving - ML capabilities are nowhere near the capabilities of a human brain.
[0] https://roxanneluo.github.io/Consistent-Video-Depth-Estimati...
So, first, this presentation we're talking about is literally about problems like that.
Second: your brain isn't nearly as good as you think it is, it's just constructing a coherent story to fool you into thinking it is. Try this on the highway sometime as a passenger: close your eyes and recite the distances to the vehicle in front of you and the one to either side. I bet you anything a Tesla is going to do that better.
Third: they pretty much cracked this already. They stopped shipping radar on US Model 3's and Y's in the spring, have shipped hundreds of thousands of them now, and there's not a hint of signal that something is off with distance measurements with the cars. My car doesn't get this perfectly (you can actually watch the animations on screen bounce around a bit as the estimates change) but I think it objectively does better than I do.
Distance/Lidar framing is old news, basically. Vision works fine. The worst bugs remaining with all the FSD Beta footage on Youtube are almost entirely pathing and planning issues. The car sees its environment just fine.