All bitcoiners will not know when that happen. We can only predict based on the price movements and the history. But that is just prediction without we know if that will really happen at that such date or year.

It is better you enjoy the ride and trying to accumulate more Bitcoin so you can sell Bitcoin in any high price you want. People can speculate that happen in the next few years but they still don't know if that really happen or not.

Maybe the thing that can drive to that milestone is when Bitcoin become mainstream and use by most people. But that could not be the right reason as we don't know for sure about that.