This Light Bulb has been burning for 110 Years straight

What is that bulb's lighting efficiency, in lumen per watt? I mean, getting an eternal lightbulb is easy. Just take any bulb from the store and connect it through diode. It will light 4x dimmer consuming 2x less power, and will probably go like that for centuries.

That 100-year old bulb was simply built with much lower efficiency built in because that was anyway much better than efficiency of a stearine candle, even taking into account efficiency of dynamo machine turned by a steam engine. Now, we have so many bulbs that we can no longer afford them being that inefficient.