"Most expected value is in the far future." Because there are so many potential future lives, the value of the far future dominates the value of any near-term considerations.
Why this needs to be retired: just because a cause has high importance doesn't mean it has high tractability and low crowdedness. It could (and hopefully will soon) be the case that the best interventions for improving the far future are fully funded, and the next best intervention is highly intractable. Moreover, for optimally allocating the EA budget, we care about the expected value of the marginal action, and not average expected value.
"What matters most about our actions is their very long term effects."
Why this needs to be retired: there are only a small number of actions where we have a hope of reasonably estimating long-term effects, namely, actions affecting lock-in events like extinction or misaligned AGI spreading throughout the universe. For all other actions, estimating long-term effects is nearly impossible. Hence, this is not a practical rule to follow.
Okay, so you're thinking about what an outside observer would expect to happen. (Another approach is to focus on a single action A, and think about how A affects the long-run future in expectation.)
Coming back to this, in my experience the quote is used to express what we should do; it's saying we should focus on affecting the far future, because that's where the value is. It's not merely pointing out where the value is, with no reference to being actionable.
To give a contrived example: suppose there's a civilization in a galaxy far away that's immeasurably larger than our total potential future, and we can give them ~infinite utility by sending them one photon. But they're receding from us faster than the speed of light, so there's nothing we can do about it. Here, all of the expected value is in this civilization, but it has no bearing on how the EA community should allocate our budget.
I just don't think MacAskill/Greaves/others intended this to be interpreted as a perfect-information scenario with no practical relevance.