I think there's a pretty simple explanation for this: It's hard to admit when we're not doing well. It's easy to say that the world is getting worse, that you're worried for the future, but to admit that you personally are having trouble is depressing and a little humiliating. I'm guilty of this -- even when times are really bad for me personally, I try to be optimistic and consider my current misery as a temporary misfortune. It helps to keep moving forwards.

This framing seems like justification of the assumption that "how the world is doing is the equal average of how everyone is individually doing". Quite simply the "direction of things" is either completely uncontrolled or controlled by a small group of people with incentives misaligned with the rest of the world. Everyone can be doing fine despite losing a war against them.

It’s also possible that what affects you personally is actually going well, but what affects everyone indirectly is not going well. Rivers of plastic may be flowing in the ocean, but your local trash collector collects “recyclables” weekly for no additional charge and you feel good about sorting the trash.