I don't think OP made the point clear, but I agree with the spirit.
Fundamentally it is this:
Sense of scale
Meaningful content at every turn
CHOOSE ONE
Examples
Daggerfall - infinite scale, but quests, dungeons, meaningful content have to be specifically targeted or else be lost in the gigantic procedurally generated world.
Elite Dangerous - spending 20 minutes supercrusing across a binary star system really makes you feel the size, but also that's 20 minutes of not doing anything.
No Man's Sky - The universe is effectively infinite, and there is something useful almost everywhere! But (almost) none of it is handcrafted, so the random content gets stale in the scale.
Star Citizen - Basically no content, but absolutely unmatched as an immersive space experience, as it doesn't compromise on scale for QoL or filler content in the slightest. Worth noting that most people hate this.
Meanwhile Skyrim is impressive because the world is pretty big, but there's also something interesting to do every 5 steps. Starfield tries to maintain this while also tossing in some NMS-style randomized infinite content, but ends up suffering the same feeling of staleness once you spend any time exploring it.