LED’s last ages... I forget the exact ratings on them, but I have personally yet never seen an LED burn out, and I’ve been using devices with them for 20+ years. If their life expectency isn’t measured in decades I’d be amazed.
I suppose the semi-conductor material will eventually no longer emit photons when a bias voltage is applied, but I agree, I’ve never known one to “burn out” after years of use. I would think in the case of these bulbs, the weak link is in the rectifier circuit.
I have -- twice. I bought a couple LED flashlights that have the cluster of LEDs. After just a few hours use, I noticed that one LED in each flashlight no longer glowed.