Endgame is just another word for having max gear in other mmos imo.

Not exactly, end game is generally the point at which you can start running the content to get the max lvl gear. Raids, ranked pvp etc.

and I see a lot of the other comments that seem to be equating "end game" with "beating the game" or winning eve.
personally I see the end game of eve as having the tools, knowledge, and capability to achieve goals, not the achievement of them itself, that is what you use to keep playing, but the ability to go after them.

I would say it is the point where Isk no longer matters as much except as a means to an end, so you make enough (either IG or out) to keep as many accounts as you want to run active month to month, and enough to easily afford any ships that you want to put on the line in pursuit of whatever it is you have fun doing.

and since different people have different ideas of fun, that point will come at different times. if small gang frigate roams are your thing, well thats gonna be much more attainable than say, whelping a titan just because it didn't have enough holes in it for your liking.