Once you see through a game's mechanics it usually stops being fun to me. A game like Skyrim, any Ubisoft open-world "attempt" or Shadow of Mordor just doesn't work for me because I see through them very quickly and you see what the game's gonna be like for the most part.
I feel similarly, though I must add that there are answers to this.
Variable content. Procedurally generated content. RNG and randomness - if your base mechanics are strong enough to support these, they're enough to mix it up and keep a game going long after you've "seen through it".
Take something like Dota 2 - same map every time, three lanes, 5v5, a limited pool of heroes and you'll have seen all of its core mechanics after 10 games or so. Yet the amount of variables (in match progression, in builds, in hero makeup) is so unfathomably complex and deep that it feels fresh and interesting even after hundreds of hours.
Take something like Spelunky. Simple mechanics, limited levels, items, short individual playthroughs. Yet the brilliant procedural generation and the way all of its elements interact with each other, continually throwing you into new situations, testing your flexibility, adaptibility and quick thinking keeps players coming back long after they've "seen" most of the game's content.
Or, to directly adress one of the games you mentioned - something like Shadow of Mordor, which manages to keep things fresh for far longer than its base mechanics would, through its nemesis system, which shapes up differently depending on what you do in your individual playthrough. It will be molded and influenced in certain ways (an important point: by your successes
and your failures) yet also finds ways to throw wrenches into your plans and manages to surprise even after longer play. It made a game that should be fun for 5 hours based on its content and base mechanics last much longer.
And to cap it off with a popular failure (in this regard) - Skyrim tries to keep players engaged with a wealth of content, but it doesn't do enough to differentiate its core mechanics while doing so. Even if you experience different content for a long time, it all ends up feeling similar. It's one of the hardest, most sudden crash landings I've had with a game in recent memory. The second I really saw "behind it", it ceased being fun or interesting. Dropped it like a hot potato.
So in summary - it's not just "respect my time" that's important, but it's also "surprise me".