Could the content be a bit more dynamic to react to your individual choices, probably, but if you want an overarching narrative going across a thousand years throughout a series of multiple games, certain events have to be set such that individual experiences don't change them.
In the case of most of the games like a Mass Effect or any of the others where decisions in one affect the next game, the timeframe you are speaking of is usually one person's lifetime or maybe 2 or 3 generations max.
You could argue that the Civil War isn't really going to mean much when some future is introduced where the next Great War is being waged, but both sides would be naturally be allied against the Dominion regardless. Add to that the fact that anyone who existed during the Skyrim timeline would be long gone, and likely several generations of offspring to boot. Lots of stuff ultimately doesn't matter in the long run. For instance, Hammerfell got pissed when the Empire attempted to cede their territory to the Dominion during the WGC. Now do you think this will make them be allies of the Dominion now in the next war instead of fighting alongside the Empire?
In the late 1700's, a group of British citizens started a civil war and thus America was born. Jump forward 150 years or so and America is fighting alongside Great Britian to stop Hitler's Germany.
Depending upon when the next game chronologically exists, likely the only lingering effects of the Civil War would be on one hand, weakened forces due to casualties during the fight, but on the other hand, each side is now more experienced in fighting a war since even ordinary people were pretty much forced into combat. The war was also a condition that needed to be fulfilled in order for them to present the return of Alduin.
The blank slate approach Bethesda took is also good for people that get heavily into RP-ing their characters. If the game were more structured to lead you to the end envisioned in the series story, it's far harder to get submerged into the RP character of your own making.
Business-wise, I also think the switchover to the next generation of consoles made focusing on the future releases on those systems far more than stuff they already made. As much as it may get ballyhooed, major distributors have to allocate limited resources (money and manpower) to where the best chance of earning revenue exists. At least Bethesda does openly encourage and equip the mod community perhaps more that nearly all developers and they really were early pioneers on going against what was thought to be common logic of locking down your product. Of course that doesn't benefit console gamers, but that limitation is on the console designers, not the software ones.
Ultimately, as I mentioned in my first post, I have gotten 2000+ hours between all my characters in this game and the DLC's. Considering the large number of games I get and then play for 50-100 hours and then am done, for me, I can't personally say I'm disappointed with the 5th installment. I can understand the points people make about stuff that could have been better, but I've gotten far more enjoyment out of it than 99.9% of games I've player through the years.
Money well spent in my book.