The problem with this model is very close to that of light bulbs. When incandescent bulbs were replaced with LEDs, the expected lifetime went from the low thousands (a balance of efficiency and bulb lifetime) to a predicted 40k hours+. It’s true the LEDs do last this long when properly driven at optimal temperatures. However, modern LED bulbs don’t really last much longer than incandescent and it’s in the manufacturers best interest to keep them this way. Cheap capacitors used in limiting current from AC sources, over driving the LEDs at high currents and temperature to skimp on costs, etc. not only make it cheaper to produce per bulb but you need to keep buying as they burn out far far before the claimed hours.
This same model applies to EV batteries. They are skimped on such that not long after the warranty expires things like coolant leaks, cells failing from defects in manufacturing, BMS failures, being over driven by excessive charge or discharge currents, etc. cause the battery to have to be replaced. Some even didn’t have any thermal regulation like the class action lawsuit for early Nissan leafs where there were extensive failures within the warranty period. So while it’s true the batteries themselves would last under ideal conditions, it’s not in the manufacturers best interest to have the battery actually last because then you wouldn’t need to scrap the car for a new one.