Schizophrenia gets worse with time, especially when treatment is not accessible. It very much impacts your outlook and happiness.
Poverty, for a lot of people, only ever gets worse - regardless of how hard they try to "put in the work." It very much impacts your outlook and happiness.
I'm sure there are a plethora of other examples. My point was that blithe comments like "put in the work = things get better" can actually cause more problems than it alleviates. It leads to a government that actively seeks to punish the people it most needs to protect, because they have convinced themselves that those people simply haven't bothered to "put in the work."