Not the first or last time certain mats are rare, Cracked Industrial Firmware was annoyingly in short supply for the longest time, now it's not even a G5.
Ironically, that was probably one of the issues that guided the development of mat' traders.
IIRC, it was cos you got CIF for certain things, while you were at a certain rank, but then, as you got promoted, the same activities would yield MEF instead.
The introduction of mat' traders, alone, would have solved that issue quite nicely but, being FDev, they had to monkey around with the BGS as part of the same update, which resulted in a bunch of other G5 mat's all but vanishing entirely.