What may we infer from this comment ? (quote below)
O'brien says " This drama that I have played out with you during these seven years will be played out over and over again, generation after generation "
Furthermore, I think you can infer that the passion and effort of the Party at this point has such weight, and such staying power, that it will never be conquered.
Orwell set out to create a horrifying image of a Party that could control not just the rights of people, but the very thought and will of them. This positions O'Brien with the ability to portray this growing evil of the Party. I would also infer from this segment of the text that the strength of the Party is just going to keep getting stronger.
They have every intention of eradicating the innate human ability to will and think for oneself. For people in Julia's generation, it will be easier to believe in the power of the Party because it is trained and engrained from birth. For each generation after, it will happen. But for those who like Winston fail to keep their ability to think to themselves, they will suffer.
I think that you can infer at least the following things from this passage:
First, you can infer that the Party will (or at least so O'Brien thinks) endure and stay in power for a long time. This is why it will be possible for what they have done to happen again over multiple generations.
Second, you can also infer that people will continue to be opposed to what the Party is doing. If people all agreed with the Party, there would be no chance for later O'Briens to persecute later Winstons.
So the basic idea seems to be that the Party will continue to exist and that people will continue to be unhappy with it.