I don't think you are wrong about it. I think it would be nice to do that sometime and TYW is a period I think I could be interested enough in to do it for a good long time.
One thing about the complexity of the rules is that it does give you time to reflect. There are a fair number of people that would think that the complexity makes the rules more realistic or makes it more of a simulation or whatever.
This time for reflection shows that they certainly do not.
Let me state that this is not criticism. The wargame is meant to be enjoyable. You seem to be enjoying recreating the action in your mind as it happens on the table and I think that would be fun too.
Most of the games I play, even fairly big ones with more than a thousand figures on the table, get wrapped up in a few hours.
There is one aspect of this that, despite the detail in the rules, makes them much more realistic than other rules that do have that detail.
And that is that you don't really have time to reflect on things. It isn't that you have some sort of limit of your time in a turn but it is that you want it to go quickly.
So you might not consider ALL the possibilities, you might sometimes just react.
A case in point.
I was playing a Warmaster game against a friend. He had Orcs, I had Chaos.
My big plan up the middle didn't work out as planned and, somewhat frustrated, I had planned to follow it up by trying to smash my way through with my Chaos Warriors.
After my big play didn't plan out my friend thought he had it in the bag. He went for a smoke break.
It was probably one of the most fatal cigarettes he ever had because it gave me time to reflect.
I came up with a different plan and smashed his army to pieces after his next turn.
I likely wouldn't have had that time in a real war.
I don't think you're wrong about it. I'd love to have a huge battle set up some time for months to game. It sounds like a lot of fun.