Did Elon actually say that the FSD City Streets Beta would be available fleet wide?
I have had the same thought about visual driver monitoring being a pre-requisite for releasing FSD Beta (although I sincerely hope they don't offer hands-free driving initially and instead wait for a few billion miles of data to come in).
I think it is implied in "the button". Elon said that the button would allow anyone (with FSD) to download FSD Beta if they want to and agree to the terms. So that would be the same as making FSD Beta fleet wide, I would think.
If only there was a tool he could use to communicate to everyone with some more detailsElon also said that he would increase the number of beta participants from the current 1,000 to about 10,000, and then eventually scale out to more people. I interpreted that to mean "the button" will only be available to the additional owners who are invited to participate. But I hope to be proven wrong.
My guess is that this is exactly what will happen. People install dashcam accessories all the time; a cabin camera seems like one of the least difficult things to retrofit onto a car. (Compare to the amount of trouble Tesla is going through to retrofit HW2 cars with the HW3 computer.)It seems a little difficult to think Tesla would retro install any cameras inside exsiting fleet for Model S and Model X owners
To be clear on the "funny" - I just think it's funny that a single word response from Elon, for something that may not happen, results in so much speculation about the reasons for this "change". But, to speculate: My thinking is that they aren't incorporating radar for City Streets right now because it's too complicated to deal with at the moment (possibly for some of the reasons you mention). In other words, I agree with what you said about the current state of affairs, though longer term saying radar is “incompatible” seems like too strong a statement. I guess we'll see if their progress in computer vision remains incompatible with radar inputs long term. I don't think there's necessarily any reason it can't be incorporated in some situations, but it's also not really necessary; certainly for City Streets it seems less useful than on the highway.
At first, it is puzzling why Tesla would remove radar. Especially so since it's been reported that Tesla was developing its own in-house radar hardware.
After giving it a bit of thought, the best guess I can come up is that the new neural network architecture in FSD Beta v9.0 is incompatible with camera-radar sensor fusion for two reasons:
First, it processes all camera input as 360-degree panoramic video frames, and Tesla doesn't have 360-degree radar.
Second, and more importantly, the ratio of deep learning research published on processing camera images vs. processing radar signals is probably like 10,000:1 or 100,000:1. A hard research problem that Tesla has been working on is how to get a neural net to compare sequential video frames, thereby incorporating temporal information into its predictions (rather than treat every still image as belonging to its own universe. It may just now be possible to do this with camera images, but I'm fairly certain it's still impossible to do this with radar signals.
In other words: my guess is that Tesla has made significant progress in computer vision, and that progress relies on a neural network architecture that is incompatible with camera-radar sensor fusion.