How does that one saying go, "comparison is the enemy of satisfaction"? Comparing subjectively different things created with different themes, goals, surrounding contexts, audiences, etc; is absolutely a fool's errand. If good quality was objective and easily obtainable it'd be trivial to produce and you'd end up with an ocean of "perfect" products, and at that point humanity might start losing its creative edge and capabilities for uniqueness or self expression (Even Touhou's dipped into a little commentary on this). Halo 1 I know has the context of being one of (if not) the first BIG console FPS games where every other game you mentioned was on PC with console ports being an afterthought. This allowed Halo to justify its weaknesses (except the movement bit) and target a more casual audience who unironically played it as their first FPS and carried that brand loyalty through the other 343 games at least.
Skyrim I know less about but it most likely has a similar context, hitting a newer more casual audience by dickriding the success of Morrowind and Oblivion, being more widely available on every console not just PC and Xbox, making itself "more approachable" etc. Even the attempted DmC reboot, closer to an objectively bad game than either one you mentioned, even matching a few of your descriptors for Halo and Skyrim
>DmC is just less.mp4
Is really just some shitty hipster-emo hack n slash that got the DMC IP stapled onto it, causing most debate to just being unfavorable comparison to the other DMC games. It couldn't stand on its own legs if it wanted to, might've even had a fanbase of people who liked hot topic and Vocaloid Screamo if it wasn't antagonistic to its predecessors and touted as DMC5. Everything I've seen of it is shit independent of those debates IMO, but we're getting to the point where someone twenty something trendsetter grew up with this as his first game and can define the "gold" he found in the shit pile.
Art, Nostalgia, Time, all three easily fuck up something that can be so simple. I'm just autistically rambling and raving about the human experience for over 20 minutes at this point, TLDR I hate art debates, subjectivity, and things being different in ways I don't like (so do you, probably), and objectively bad "should" exist and does for Jekyll and Hyde etc, but seemingly can't for anything that gets a big enough audience, has a certain context, "unique" selling point, etc.