I think people oversell the concept of "immersion." There are plenty of old games that wouldn't be immersive to gamers now, but they were and maybe still are to some who are willing to overlook some things. The suspension of disbelief is a choice too.
But, hey, I'm talking to a guy who compared age resets in Civ7 to being fired. We're firmly in overdramatic territory here, which is part of the landscape of modern gaming, for better or worse.
First of all, I did not 'compare' age resets to being fired. I said that approaching a forced event with mostly negative consequences with some kind of 'positive outlook' is similar to that as if you got fired (as to make a similarity to point out that the thought process is infeasible).
Of course, playing a video game and losing something is not going to make me rethink my life as being fired, that is dramatic.
I will dissect the situation in a way that I hope represents player feelings and opinions:
Here is a crude illustration. During the black parts of the playthrough, the player is in complete control - he sees everything that happens in the game,
His actions have direct consequences. Harkening back to a previous commenter's thoughts: This is the period of time where, when you get Shot, you take Damage, and you Lose.
This is where wins and losses are realised by players.
When the age reset happens, it is mandated by the narrative even if you, the player, are winning heavily, or losing heavily. Somehow, your prosperous nation has to somehow lose military and cities, change culture, and all this over a cutscene.
So the loss in immersion happens during and after the reset. As you can see, once the player regains control of the game, he is in a different state to where he left it, and it is through no control of his own, and he has no mandate over the fact that the reset has to happen.
If the game was aiming for true immersion, then this type of cultural reset would only occur once your nation was verifiably underwater - and as a consequence of your own action - and not necessarily mandatory.
As an addendum, I find many old games immersive despite their many flaws because they understood player preconceptions better at the time, since gaming was not as big, most players were pure casuals and so they had to make games understandable by their standards.
That's why many old games live the test of time, people still play old 4X games, old RTS games, old shooters and so on. While their flaws are usually in lack of complexity, their strength comes in being a well-refined product with good immersion from start to finish, generally good recognisable music, and a good understanding of their target audience.
4X and RTS are not dead genres as some people suggest, and their newest games are not flopping from a lack of player-base, OR a lack of developer resources; I believe they simply deposit the resources in the wrong place, usually for profit incentives.
As time passes, if Civ7 is to be successful, I think you will find Civ7 pivots hard towards improving player immersion, quality of life, user interface, music, because those are the things that stick and get people to stick around.