Some sanity check math:

Directional LED sources (LEDs, optical system, driver) are around 100 lm/W (some are a bit higher, some are lower, but this makes the math easy), so for 800 lumens out the front, you're talking roughly an 8W source. We'll ignore the heat implications of that 8W source for now, and focus on the batteries. For 6 hours of operation, that's 48 watt-hours.

A 3500mAh 18650 is about 12 watt-hours, and a 5000mAh 21700 is about 18 watt-hours. Those 48 watt-hours need 4x 18650, or 3x 21700 cells. So about 2 hours of 800 lumen operation per 21700 or an hour and a half per 18650. Moving up to larger sizes, a pair of 26800 or 32650 cells would come close to having enough energy - you're looking for around 14 amp-hours.

Looks like the Lupine units have sufficient battery to deliver the output and runtime they claim, but the Fenix HP30R steps down somewhat from the rated output in order to achieve the claimed runtime.