I concur, and this is the only area that, IMO, civ fails at and has failed at since civ III. Since those days (civ III vanilla, that is) the franchise has consistently provided the most exciting, entertaining, and thought-provoking game on the market, and a TBS game no less. Yet every single permutation in the last decade+ gives you a game that consists of two halves:
1/2:the most exhilarating adventure,as you build stronger armies and add multiplier upon multiplier to your exponentially stronger cities, carefully calculating build queue decisions and unit placements, and
1/2: the most tedious process of wrapping it up. Victory is usually decided and almost unavoidable hundreds of turns before it is reached,yet you still have to turn-click, skip moves, turn-click for hours on end. Finishing this game requires work ethic.
The process of creating a winning scenario is incredibly fun, but actually using it to win is incredibly tedious. So much so that someone with extraordinary patience could turn a pretty penny finishing other people's games for them. I may work with autistic children 60 hours a week, but I don't have that level of patience.
Seems the designers need to either A.) find a way to make the end-game as fun as the beginning, which I'm pretty sure has been a priority for some time but is as problematic as ever, or B.) have an auto-finish option. Seriously, around the mid-industrial era, have a pop-up that says, "I see where this is going" and auto-finish the game. It's kind of like the "retire" option, but that's more for losing; retiring is like admitting defeat in chess when you have only your king against king/knight/bishop: you're gonna lose, but you could pointlessly dance around the board for a couple hours until that VC is achieved.
Apologies for ranting at length, but as this is, IMO, the best game on the market, and every few years they release a new, even better version, yet every version has just one downside, the SAME downside year after year, and this forum discusses that franchise, it seems appropriate.