This is why the next Civ game should endeavour to put much more emphasis on survival and sustainability of civilizations. Insofar as it is unrealistic to have individual civilizations go from strength to strength for 6000 years, it is also unrealistic to have civilizations/leaders planning for UN or Spaceship or even Conquest/Domination victory as their ultimate goal throughout the game.
Civilization is a way for groups of people to maximise their own welfare by exploiting and attempting to contain and control the natural world. Throughout history, civilisation advances (including but not limited to science and technology) have developed/evolved in response to particular problems and circumstances faced by different societies. Civilisation advancement has rarely if ever been conscious or part of a clear long-term strategy e.g. "It's 800BC so I'll research Writing so I can beeline Liberalism and grab Economics and adopt Free Religion and Free Market in about 2000 years time" , but civ games tend to encourage both human and AI players to play this way.
What a future civ game ought to do, imo, is encourage players to approach the game more like this:
"Okay, I'm in the ancient era and I have three cities and am being assaulted by a constant stream of barbarians, my water sources may dry up due to overuse and/or the climate becoming drier and my arable land may become depleted from overuse. Meanwhile my people's health is limited and living standards are generally low, and this may cause civil unrest and rebellions if I don't look after it. So should I concentrate my efforts on finding ways to improve my people's health, building better weapons to fight off barbarians, or facilitating trade and improved management of my natural resources?"
Admittedly, Civ4 was quite good in some ways at getting the player to "Play The Map" like this, but there still wasn't enough focus on immediate needs when compared to goals in the distant future, because the pressures on a civ's survival and ability to sustain itself over the long term weren't really all that compelling compared to the pressure and impetus to become a superpower and win the game. Perhaps the next civ game should have a "blind research" option like SMAC with different categories of techs you could prioritize (e.g. "growth", "commerce", "military", "living standards"), along with research being dependent on available resources e.g. can't research horseback riding if you don't have any horse resources.