It does seem a poor example, but I guess the intended point is that the logical decision should be "will I more enjoy going, or not going?" rather than taking the already "sunk" money into account. Of course in the real world, especially if the money was a significant amount to you, your enjoyment of staying home might genuinely be tainted by the wasted money, and that's just as legitimate a factor as anything else figuring into your "based on where I'm at now" assessment.
I think a better example, maybe appropriate to this forum, might be where you've been spending significant spare time working on a project with dreams of future riches, and it eventually dawns on you the payoff isn't going to happen (maybe the opportunity has passed, or whatever - reason doesn't really matter). The question is do you now continue working on the project to "at least get the satisfaction of completing it, given how much time has been sunk", or do you cut your losses and abandon it. Even this isn't a "pure" example since there's no reason not to continue if the modified goal (satisfaction) is worth the remaining cost to you.
It's probably the case that in most, maybe all, "sunken cost" scenarios there is some benefit to continuing to invest in it, but the "sunken cost" may distort your judgement of assessing that benefit. Even with Concorde, there was considerable cachet and advertising benefit in operating Concorde, even if it wasn't paying for itself operationally.
I think a better example, maybe appropriate to this forum, might be where you've been spending significant spare time working on a project with dreams of future riches, and it eventually dawns on you the payoff isn't going to happen (maybe the opportunity has passed, or whatever - reason doesn't really matter). The question is do you now continue working on the project to "at least get the satisfaction of completing it, given how much time has been sunk", or do you cut your losses and abandon it. Even this isn't a "pure" example since there's no reason not to continue if the modified goal (satisfaction) is worth the remaining cost to you.
It's probably the case that in most, maybe all, "sunken cost" scenarios there is some benefit to continuing to invest in it, but the "sunken cost" may distort your judgement of assessing that benefit. Even with Concorde, there was considerable cachet and advertising benefit in operating Concorde, even if it wasn't paying for itself operationally.