The problem with the world improving in an irrefutable way on average is that this can be and is used to defend the status quo in almost any field and can lead to complacency and a false sense of optimism. The world became better due to science, technology, various policies, cultural changes, etc. and will only improve if these are continued. It is not always clear what brought improvement and whether that sort of improvement will keep scaling. This is just my long-winded way of saying that I don't like it when people say the system is great, don't change anything, don't complain, and in a few more generations we'll all be fine.