1. Who says he has had to fight off anything in those 200 years? Nothing suggests anything has directly raided your house in that time.
2. All robots are powered by nuclear batteries, which, as shown in every Fallout game, are stil viable even 100-200+ years after the war.
3. Raiders attack your settlements because people are actually living there, and thus there are people to raid.... no one was living there before you founded the settlement, so there was no one to raid, and no reason for raiders to go there.
The lore is that the resource wars were started over oil, but by the time the great war happened, oil wasn't the main concern anymore, it was simply winning. Oil was the initial catalyst, but it wasn't what mattered the whole time the war was going on. reasons shifted over time, just like they do in wars IRL.
Where do you think all those randomly encountered hunters come from? The various towns across the wastes.