But it's not an either/or situation, you can just do both. FOB invasions can't take any resources from the stuff you've fultoned in the game. So reverting your save only means that you don't get the processed materials from the FOB and save a few staff members that might have been lost in invasions.
And that's what most of us care about. Most of us don't care about F.O.B. processed minerals when again, you can get a faster increase doing checkpoint exploiting at airports for the same increase.
"Oh but they're entirely separate?!"
Again: Who cares? Oh noes, the 200-3,000 minerals that I could've gotten in a 24 hour period and have had stolen along with staff is lost! *yawn and revert to save that doesn't have staff loss and get 7,000+ within 5 minutes of play start*
Doesn't seem counter-intuitive, seems like exactly what they were going for. An economy system. While combat is more viable a play style than ever it is clear that they want to keep the game from just being a bombing run on every mission. Even the story is frequently mentioning cost and logistics of war.
No, I get that. Bombing Runs and Resupply drops? Sure, eat my GMP.
Me wanting to get to a mission within 30 seconds over the two minute intro swooping in? No, don't eat my fucking GMP for upgrading for the sake of "better performance."