three GECKs in the series total. The Enclave and the Master were bad guys, sure, but they're not exactly the root cause of everything bad and terrible in the Fallout verse
Three that they had... and the Enclave were the root cause of everything bad and terrible in the fallout verse.
Without them the underlying problems can start to improve themselves and they can begin to collect the Gecks.
Quite literally the Enclaves destruction should mean much more.
I don't want to spoil too much but suffice it to say that they were the secret villains of the first game and the outright villains of the second and third. They instigated the entire series and were the cause of everything.
What is odd is the Enclave had a reason for doing what they were doing... but that goal was long lost.
I mean I guess you could have taken out a fake Enclave who were fooled by the real enclave.
The Enclave may have caused everything... But their destruction simply means they have stopped doing bad things. Really, the Enclave weren't even the cause of the Great War. They didn't cause humanity to run out of oil. They didn't make the nations fight amongst each other in order to gain the last drops of oil. They may not have even pressed the button to launch the nukes. Nobody knows who fired first. And the GECKs wouldn't solve much of anything. You gotta take out the ones in the vaults that had gone bad enough to break down, the GECKs that had been wrongly placed due to clerical errors (Vault Tec were quite bad for that), and the ones that might have been broken unintentionally or intentionally. Then you have to assume the person who has the GECK knows how to operate a cold fusion reactor and can read the manuals. Then you have to plant the seeds after purifying the ground. The problem is, though, that just because you've got a GECK that the rest of the world will fall into place. The GECK can't cure homicidal mutated animals, raiders, or desperate people who would really like some of that food you have there. Though, I'm going off of knowledge from the Fallout Bible. But my last point stands: even if you have a miracle machine, it's not exactly smooth-sailing from there on out. There's still bad people out there.
Isn't that where House or the Courier comes in?
That is kinda a glorified city state, though.