So the answer IS as I suspected? The current gameplay mechanics means you basically never use the abrasion blaster or sub-surface missiles on any asteroids other than motherlodes?
Demonstrate the choices open to you (and us) and go and mine void opals or anything of worth via something other than motherlode -> motherlode -> motherlode? Because I think you'll just ignore asteroid after asteroid after asteroid, rarely finding anything of interest/worth. And this current balance controls most people to instead just motherlode -> motherlode -> motherlode.
Personally I think the current mechanics and balance are skewed. I think you SHOULD be able to hunt solely for motherlodes if you wish, but that also a good income should still be viable from the lower part of the pyramid by finding plenty of valuable (wanted) materials from surface and sub-surface deposits...
What? You are claiming I said the opposite of what I said. I used the abrasion blaster last night. Also the mining laser, the subsurface missile, and the seismic charges, all on a variety of asteroids.