The issue with bronze is the scarcity of tin (or the toxicity of arsenic, if one is making arsenical bronze).
But yeah, one can just cast bronze much more easily than one can cast iron. The melting point of bronze is about 200 to 300 C lower (and 500 C lower than cast steel.)
what prevents bronze from being "worked nearly everywhere by nearly everyone" or to put it another way what make iron easier to work?
If you had asked me I would have said the opposite. bronze is nice and easy to work while iron requires much hotter fires and harder implements.