Ya but... A major reason I like the TerrsLux drop-in LED bulbs is this line in their write-up
Quote:
... contain the TerraLUX LED Light Engine, so it maintains a constant light output over the life of the batteries. ...
That tells me that the LED bulb has a voltage regulator or something similar to maintain lumen output. An unregulated LED can still have very good life and is not fragile, but voltage regulation helps get the most out of your batteries.