The problem really is, how they want to prove the lifetime claim. Sure, many wear mechanisms could be accelerated, many could be extrapolated (smaller drifts observed over shorter time, assumption made on how these will play out after the 50 years), but even for life rating below 20k hours the LEDs are facing many issues where neither method was able to predict them.
Plus if the lanterns are to be designed as not user serviceable (so needing a qualified electrician to fix once it fails), standard "xxx% survival" metrics becomes nonsense (regardless when that percentage is to be a bit above 70% or what), but a kind of "xxx ppm failure rate" or a MTBF metrics, same like with any other equipment (like heaters, fans, HVAC, circuit breaker panels,...) should be used. And when compared to that, the LED lifetime is barely fraction compare to what is common across such devices, far too short for being a "not consummable" sort of a thing.
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