Are you actually under the ridiculously naive impression that hard work = success? I thought that had been satisfactorily disproven years ago.
I can "work" very hard pushing stones uphill like Sisyphus, and I probably won't get rich as a result.
A major reason why inequality exists is because the work ethic required for long-term thinking and planning is a model of behavior which children acquire from their parents through learning, observation, and imitation. Children from families where parents do not consider long-term goals worthy of pursuit are hugely disadvantaged.
I suppose it depends on what you mean by success. But by the most common definitions (e.g. being rich) hard work isn't the main factor or even required at all (e.g. inherit millions from your parents requires how much effort? Basically not dying).
I watched my dad hold down two jobs and come home and work into the night providing his family with the things we needed. The first career job I had made more than he's ever made in his life and that job was mostly standing around.
Sadly, how we really wish things were has nothing to do with how they actually are.