Why do my huge bone broth ice cubes become tiny puddles when melted?
We (humans) can be pretty bad at estimating volume by eye, especially if you're putting a bunch of cubes in one bowl - they don't pack efficiently (there's a lot of air in there). You might not actually be losing that much volume.

For example, I just dumped out an ice cube tray full of cubes, and they looked like a bit over 2 cups, but once melted (and I checked by weight, I didn't lose any!), they're about one cup:

 

The ice is a bit (~7%) less dense than water, but the rest of that apparent 2x reduction in volume is just the packing inefficiency. Depending on the size/shape of your cubes and the size of the vessel you're melting in, it could get exaggerated even more.