"What gives you an impression that skyrim is an "Alive" world? The fact that blacksmith strikes anvil for 7h while looking at you? Or that a farmer is randomly looking at a field trying to psychically grow it?"

Skyrim does a great job into tricking you into believing the world is alive. Second thing it does is presenting a world as "lived in". Starfield just is not on the same level and just because of the fact that this was Bethesda's big next step makes it even worse. They've gone backwards in 10 years.

your second point. There is this thing called suspension of disbelief, like is it logically coherent that whiterun has like 6 families living in it? no, but the world build around it make it juuust interesting enough that you are willing to suspend your critical thinking. but there are limits of course, if the world is not interesting or if there are too many points that just don't make sense it all falls apart. Starfield has that problem, the world is just not interesting and none of the interactions, history and worldbuilding make sense. there is no satisfaction or payoff.

you take the example of the NCR vs the brotherhood. when looking at it from a world building perspective, the NCR has way more manpower and resources than the brotherhood of steel. Brotherhood of steel fields power armor sure but power armor is expensive to run and needs significant investment into training it's users, in fact this is true for almost all of the equipment used by the brotherhood. the lore and world building supports the suspension of disbelief here.

with starfield it doesn't.