This sounds like the RNG just being itself tbh.
Every game seems to pick on certain items to 'weight' and others to be stingy with.
In my current game Prox. Launchers may as well not exist. I had to use contacts to get any at all. But in my previous, I had enough to put them on several ships and still have leftovers just from bounty salvage.
The exact same thing happens with colony items.
Some games you'll see a huge pile of <x>, but others you'll struggle to see even a single <x>.
It is also a PD weapon
Which is code for "make something right next to you very unhappy".
Prox. Launchers are (imo) one of the best 'assualt' weapons in the game. Find a ship that can mount multiple forward facing launchers, and just fly towards something (the closer the better) holding down mouse1 while cackling like a witch as <thing> dissolves in a cloud of obnoxiously purple mist.
They used to be bad. Really bad.
But they own now thier prox. radius was fixed.