It doesn't explain why they did not turn feral by 2241 and have begun to turn feral by 2277.
Nor does it truly explain 'why' they turn feral. It has speculation, but speculation ain't concrete facts.
The speculation does add up, don't get me wrong on that, but at the end of the day it is just speculation.
Is it because of mental disorders? Is it because the mutation is deviating? Is it because of radiation? Is it because of the brain simply deteriorating?
Barrows doesn't explicitly state what exactly turns them feral.
He partly explains the process of how the mutation of feralization occours, but he does explain what causes it to begin with.
Nor does it explain why they can sprint faster than a fit healthy human being when their bodies are supposed to be rotting away.
My problem with feral ghouls is that they are just shoehorned into the franchise and we're just supposed to accept it.
No, I will not just accept it. Feral ghouls, the way that they are depicted in Fallout 3 at least, can not just be thrown into the world of Fallout without a damn good explanation for it.
Up until 2241, no ghouls have been portrayed like the ones who are feral in Fallout 3.
At 2277, now there are feral ghouls all over the place.
That does not make any sense to me. Bethesda's Fallout 3 and even FNV acts like feral ghouls have always been around when they have in fact not.
It'd be like a tv-show just suddenly adding a new character and every other character knows who this one is and has a history with him and references previous episodes as if he was in them.
It's bad writing/design to just shoehorn in something without a good explanation.
Whatever Barrows said it does not give us a full explanation or justification for why feral ghouls should now be a part of Fallout.