I already wrote a thread about the current state of the game pacing, even in endless.

I'd like to pinpoint more precisely the issue of the AI rushing the last era not to be able to close the game.

Elissa got to the last era turn 302:

Victor around turn 315-320:

While, I left the medieval era (yes, that one) around turn 290.

The issue is not really there, they both had more fame than me, better armies and seemed ready to win the game.
However, they did not found a way to end the game. Science was obviously one part of the explanation for Victor (Blue) but not for Elissa (Black):

And the research graph:

They both had researched more technologies than I and could have gotten to mars before me.

I looked at the end game recap and noticed the following science stars:

1. Elissa: 3-3-3-2-1-2
2. Victor: 3-2-2-3-0-1

So, they pretty much fall down down at the end, after both good start and I don't get the reason to reach as fast as they did to the last era with only 1 and 0 science star.
I'm pretty sure there was a window during which either of them could have won, of maybe close to 70 turns (I had some point in the sleeves, but not enough to close the whole gap).
If Elissa had directed her research on going to Mars, she would have won.