Receiving power isn’t the same as being “on”. I’d assume the drive has a sleep state that it goes into after inactivity, and those hours don’t count as “power on” hours.

Interesting, thanks. The spec does leave it almost uselessly underspecified:

"Power On Hours: Contains the number of power-on hours. This may not include time that the controller was powered and in a non-operational power state."

The same drive reports only 329 "controller busy time" minutes.

My 960 Pro 1TB, which I paid way too much for back in the day is at just shy of 5,000 hours, and I've used the hell out of it since it was new.

960 pro was released in October 2016, even if we assume you purchased it the same month it was released, and you have been running it 24/7 non-stop, that's 50,591 hours counting from October 1st to this hour. I can assume the number is way below 1/3 of that even for people that use it 8 hours a day.