it seems most plausible to me that reality is something we each get to decide what is.
It sure is! If you can imagine it, you can do it, or at least get closer. So try! Like these people you describe:
When I encounter someone who firmly believes they will always succeed, I see them as "unrealistic," even though their actual experience may well be that 95% of what they attempt turns out well!
Most 50 somethings, even today, have the same values your 50 something parents had - keep the money coming in, the house standing, and your stuff up to snuff.