Just looked it up aaaand…huh…I don’t think I hate it

Basically there’s an ‘age’ reset which resets everyone’s tech level back to the beginning because now there’s new age tech and the old tech is obsolete; tech progress resets. If you lagged behind during an age, you’re now back to a level playing field. Apparently one of the intents was that some civs that had early game advantage can now carry that advantage with them until the end (in some manner; I’m not sure how exactly it works).

Although it is admittedly more of a crutch for low-skilled players (like myself) that doesn’t have anything to offer high-skilled players.