Unless they make these windows out of some kind of futuristic glass, any paramedic, firefighter or police officer would/should have a glass breakage tool which would quickly break the window, so I'm not sure about the "several hours" claim.
Not defending Tesla, but electric windows in preety much any vehicle will fail once a vehicle is submerged, and the pressure differential makes opening the door impossible. I've worked a lot of submerged car deaths, many in shallow ponds.

If you ever find yourself in the water, IMMEDIATELY open the window or door, preferably while the car is still floating. Don't wait for the electronics to fail or the car to sink. If you do get submerged, once the pressure is equalized, the door will more easily open.

And lastly, get every member of your family a combination seatbelt cutter/window breakage tool to keep in their cars.

I have been retired for more than a few years, and just discovered that y knowledge on this topic is out of date. For decades, vehicles had laminated glass windshields (with plastic sandwiched between layers) and tempered side windows (which shatters into little cubes). I just learned that newer vehicles require laminated glass for side windows (It was unclear to me which windows and vehicles are affected). Window breakage devices (hammers and punches) won't break through laminated glass.

The reasoning behind this is that the laminated glass prevents ejections. I would say (based on my experience) that ejections are far more common than drownings, and that may be the determination the regulators made as well.