As pointed out in the article the LEDs just fade away. This means that if you define "lifetime", you also need to define how much you can lose brightness to still considered it to be alive.
Could it be that with the initial 100k LEDs the definition was different than with current ones? As mentioned, the industry is now using the 70% of brightness as the limit. Since such figure was probably not defined early on, maybe the vendors put the limit much lower.
Could it be that with the initial 100k LEDs the definition was different than with current ones? As mentioned, the industry is now using the 70% of brightness as the limit. Since such figure was probably not defined early on, maybe the vendors put the limit much lower.