To be fair, the Tesla vision system has 3 cameras facing forward. One in the center above the front bumper grille and two behind the rear view mirror. Those two provide some level of stereoscopic vision to help judge distances.

But yeah, the lack of other sensors is a huge issue. Anything from bug splatter to mud to snow etc. can easily obscure one or more cameras and render the whole vision system unreliable.

We also process light differently than cameras do

To expand on this a little further, human vision has also developed the ability to filter out unnecessary information in order to avoid overloading the brain. When tracking moving objects the eyes mostly send deltas of the movement to the brain. Computers, however, are the exact opposite. The cameras essentially send a series of still images, and it’s up to the computer to compare them to look for any movement.