I can't speak to caving, but Lupine is regarded as making probably the best and most powerful mountain biking lights there are (and some of, if not the most expensive), and have maintained that position for many years now. They have stellar customer service, amazing build quality, a huge amount of options for batteries, configurations etc., and unless things have changed in the last couple years you could upgrade light heads as advancements are made with relatively low cost compared to replacing the light. The only complaint I've ever heard about them is the price, and most once they pay it, would happily do so again.
I've never owned them but have used a few cycling buddies on rides and have always been very impressed. Not sure if it would work for caving but I've used Light and Motion lights (they also do scuba lights) on the mountain bike for years, and never had any issues.
One thing you'll find with bike lights, while they do report ANSI runtimes, when you look at their discharge curves they don't game the system like most flashlight companies do you get near max brightness for most of the runtime claim. Cyclists would never tolerate their lights stepping down to 30% of the rated max output only a few minutes into the runtime claim.
The Light and Motion 2000 seca enduro light for example claims 2000 lumens on high for 2.5 hours, and 95% of that runtime on high is spent above 1900 lumens. They do have a new 2200 model out that is IP67 rated.
On Lupine's webpage they don't list any of the Betty/Wilma lights under the caving activity tab, you may want to check with them why they don't list them for caving. They do list both the light and battery as IP68 rated.