I completely erased my MGSV save game data because I was messing with FOB stuff and decided I wanted a fresh start with everything, you can't remove the FOB sadly, it just resets the FOB's progress back to how it is before you upgrade anything.
I was already annoyed at the tutorial forcing me to build one anytime I automatically went online until I caved because I didn't want to relaunch my game to get back to a menu to go offline.
Going offline with your FOB left vulnerable or restarting your singleplayer game while your empty FOB is open to attack until you get back to Mission 20 or whatever is some serious bullshit.
The limit lift on resources was also a pretty goddamn dirty trick as they don't tell you that they'll rob you of a good chunk of your singleplayer resources (I actually lost like 90% of all my collected vehicles offline)
This is the way it should be done,
IF AND ONLY IF you cap out on a resource, then the overflow should go towards your FOB inventory automatically.
OTHERWISE, it should let you
CHOOSE exactly how much of anything you have you want to transfer to and from your Offline/Online inventories.
WAIT
So there's this event stuff now for FOBs
It's not actually a real player you're invading though, it's a CPU/bot.
So once you invade in that event thing, the CPU can invade back
CPU is programmed for instant win and can't lose.
You lose a max amount of resources with every invasion.
You have to buy insurance for the game to stay playable.
That literally makes no sense, prove it, otherwise don't be a fear monger.