I'm glad that you think 6v lanterns are useful, but maybe the "box batt" doesn't last ten years. It's still alkaline remember.
About 6v lanterns, I've had some bad experiences with a $4 dorcy lantern. It looked very good when it arrived home, but with some scratches in the lens. Compared to 2d lights, it was plenty bright, but not as bright as desired. The bulb was a plain vacuum 4.8v .5A bulb that blackened over time. On the second battery, (the first was included--a cheap "heavy duty") the bulb gave out. Frustrated, I cracked the lens by stabbing it with a pair of scissors. I did not care to get a new bulb but proceeded to drop test it without batteries. The bezel assembly cracked.