Suppose you have a dozen problems in your life that you are trying to solve. And suppose that whenever you try to solve one of them, you almost always fail. Is there a chance that a time will come when you have solved them all?
There is such a chance, of course. You almost always fail, but if you continue to try other possible solutions, you might hit on a solution sooner or later. And then you will have only 11 issues remaining, and you can continue from there, working on the next one.
And even after more or less resolving one problem, you might later discover a still better solution. Thus for example I discussed a certain solution to time management here, but my current solution is substantially better, although including important elements of that one.
In a similar way, I discussed the general idea of progress in the posts here, here, and here. A very simple summary of the ideas argued there is that people are trying to make things better for themselves and others, and even if they do not always succeed, they sometimes do. And for the reason assigned above in this post, you do not have to succeed in solving your problems all of the time, or even most of the time, in order to generally make progress.
In economics, there is a similar reason for the fact that markets do as well as they do, and in biology, why natural selection works as well as it does, despite the fact that a majority of individual changes either do nothing or are actively harmful.