Really there is no true answer and its completely up for people to speculate and debate about. I'll just say this. Season 4 of the game happened roughly only about a year after issue 192 took place. At the point of issue 192 things weren't even close to getting to where they were at issue 193 (only a handful of the people from the Alexandria area even knew about Commonwealth yet and most of them were pretty skeptical of it). It would have taken quite a while just for them to get acclimated to the Commonwealth let alone them feeling comfortable enough with it for them to start recruiting new locations into the Commonwealth.
It would have likely taken a good nother 5 to 10 years after TFS for places like Ericson to be discovered and brought into the Commonwealth. To say those kids would have lasted that long is highly debatable.
But again there was no answer given within the TWD universe so people are pretty much open to believe what they want to believe and debate it with eachother.