I attribute a lot of it to steadily increasing dynamic ranges of camera sensors. Between my two Olympus cameras, it increased over four EV.

The other thing I did to help was try to isolate the highlights and the shadows during processing to optimize each as best as possible. That involved a lot of masking in Photoshop. For example, in this photo, I used a vertical mirrored gradient mask down the center to separate the stalactite from the background and then worked on the two sections separately.

It took a lot of work, and I left many photos on the "cutting room floor", but I did like what I got from available light photography under demanding light conditions.

Careful taking that first bite! LOL