In fact, by the time the crash happens, it’s alerted the driver to pay more attention no less than 150 times over the course of about 45 minutes. Nevertheless, the system didn’t recognize a lack of engagement to the point that it shut down Autopilot
I blame the driver, but if the above is true there was a problem with the Tesla as well. The Tesla is intended to disengage and disable autopilot for the remainder of the drive after a small number of ignored alerts. If the car didn’t do that, there’s a bug in the Tesla software.
I think it’s more likely the driver used a trick to make the car think he was engaged when he was not. You can do things like put a water bottle wedged in the steering wheel to make the car think you have tugged on the steering wheel to prove you are engaged. (Don’t ask me how I know)