a lot of time it's not the battery that is low quality but the electronics that manage it.
batteries usually come from the same suppliers but everyone develops their own battery management.
if you either over-charge the battery or over-deplete or charge too fast etc. the battery will degrade rapidly.
this is actually one thing Tesla is good at. their batteries last longer than almost any other electronic device, even though their cells come from common suppliers like Panasonic.
Tesla knew that as a company they would not survive if their batteries didn't last because the battery is under mandatory California warranty and is the most expensive part of the car - so as reckless as Tesla is with human safety they are actually conservative with the way they manage the battery.