Simply put, LED Lamps will not last forever!
LED Lamps like any other electronic device are made up of complex electronics, the light emitting diode being one important element that produces light, but the way in which the diodes are energized is just as important!
Most LED lamps have a L70 value stated on the box. This is often identified as how long the lamp will last, however this is incorrect. The L70 value makes reference to what period of time elapses before the initial light output has diminished by 30%, hence it still produces 70% of its original output.
These are actual measured values for the diodes, but what about the power supply where far more electronic component reside? If one of those fails, the resulting effects is an inoperative light. So a better way to determine longevity would be to find out how many lamps have survived to the stated L70 value, as a percentage of lamps produced.
LED lighting is complex and product should be sourced from reputable companies who understand both LED technology and lighting design in the built environment.