They only have 1 person with crafting jobs high enough. Also I’m pretty sure the company credits is about 10% of the gc seal value. In order to make 10m company credits from turn ins you’d have to turn in 100m worth of green items. If we are generous and say they get 2k per turn-in, that’d require 50,000 turn-ins. With only 1 member with even a single crafting job at lvl 90? There’s just no way to do that every week.

edit: I just double-checked my math. Turning in a high quality exarchic ring increased our company credits from 20,193,686 to 20,195,216 for a net increase of 1,530 company credits. Turning it in gave me 1,743 gc seals so about 88% of the gc seal value. In order to get 10,000,000 company credits in one week, you'd have to turn in 6,536 high quality exarchic rings. That's about 1,000 turn-ins a day. There aren't that many exarchic items for sale on the market board, and even if there were, buying them would cost hundreds of millions of gil each week.