I am confident the act of completely running out of fuel is what causes the damage. I just go to 90 Km past the warning, which is triggered around 10 to 12 of the tank capacity, I go to until it settles on 3.9% for the first time.
What would that be 1 to 1.5 inches of fuel depth when the warning comes in? How much of the actual electrical motor is submerged in fuel then? However it seems that the fuel flows through the motor assembly to also provide direct cooling to the motor. Which supports the idea the low fuel level is not being the culprit. Running out and having air flowing through the impeller and then through the motor I can certainly agree on.
The shop guys have always told me the it is the lack of liquid at the impeller that causes the damage. it is required there for lubrication while running.
Keep in mind I buy gas once every four days. I have no interest in turning 5 stops a month into 10 plus, that is a lot of time over a course of a year lol.
30 years of driving with this habit, have not lost a fuel pump yet.