What I find remarkable is that there are two inexpensive choices available right now in common US brick and mortar stores that can do 500 lumens for over 4 hours (per manufacturer’s ansi FL1 claims). No ordering from specialty shops or overseas needed. Of course, they take 3 C cells instead of the desired single cell, but pretty darn close.
Costco Feit Electric 500 lumen
The Feit is small enough to carry around in a bag, the HD light is larger.
I find it mind boggling how far we’ve come in the last ten years.