Probably an odd question as it pertains to myself specifically, but I thought maybe others here have had similar experiences and can tell me.
When I was a kid I used to really get immersed into the games I played; I'd feel as though I was actually, feeling the very walls around me in dungeon crawlers, getting tense in fights and such, but nowadays I don't really get that sense any more. I'm in my mid-30's and now I'm thankfully able to afford any game I wish, I thankfully can choose how long I spend gaming, yet I just can't get immersed, I just can't get pulled in anymore.
My buddy told me about the Witcher 3 and told me it's great and immersive like only the oldest games ever were, and yet when I played it....I got kind of bored, and lost interest somewhat fast. One possibility is that maybe with modern proliferation of game knowledge, we can simply google for anything we want rather than let the game help us find what we need, pulling us out for that much of the game, another possibility is that we recognize mechanics and animations for what they are, and we try and memorize enemy combat animations, and our own iframes and such, even if instinctively.
I honestly can't remember the last game I played where I got immersed into the game and just felt the world rather than just see it.
Immersion comes from mystery, mystery fades with age and familiarity with the medium and its tropes. It sucks obv but it's not abnormal.
On the other hand, media savvy is it's own form of enjoyment, a second level of critical appreciation for the craft and all the various tricks and mirrors game devs use to make the good brain chemicals.
Also since everyone else is recommending games, I'll throw out Disco Elysium and Sunless Sea. Not quite "immersive" due to the obvious game abstractions from the story (and imo unnecessary burden of collecting money in both games) but they give you so much well-written and unique story to chew on and wonder about.