Survivorship bias is where the data you are looking for is biased based on the fact that those who died (sometimes figuratively) can't provide data points. For example "Raising kids isn't that hard. My parents did it." I'm looking for the thing that happens in the other direction, where you assume you will survive (or sometimes just succeed) because whatever you do won't matter if you die (or fail). The most common place I see this is in the phrase "We will, because we have to." It's something someone might say to indicate that they have stopped considering the possibility of failure because it is not helpful to consider it. This thing that I don't have a name for is also the justification for lying to kids in an emergency by telling them that everything is going to be OK even though you are unsure. If you all die it won't matter that you lied to the kid, so you plan assuming you will survive.
Apologies for not being able to explain that better, but that really is the core of my problem.