I bet if you took a 1000 long-life rough treatment 240V bulbs and put them in 110V surge suppressed and line conditioned sockets several of them would last 100 years.
They just happen to have noticed that that bulb has lasted that long, numerous bulbs - exactly similar and made by the same company have burned out long ago, we just don't keep track of them. We also don't run them on a line conditioner and surge suppressor. Does not surprise me in the least.
Does it say that the bulb is installed on a surge and line conditoner?
It's a 4 watt bulb with a VERY thick filament.