I don't think it's money issues, I think it's more of art of craft, and too much grind to unlock all those part when want to be good art of weapon right off bat rather than many real day later.
I think some want to craft personal weapon, but to do that, they want unlock all kind so they can pick and see, rather than grind too many day later.
If op want cheat, he or she can do cheat to get money, but that is not all about.
Personal, it's should not locked in normal gameplay because it's too much grind, not because of money, no, but want to craft of personal weapon right off bat, but can't do that till all craft unlock then see what they like.