Land Of Opportunity Meaning

Example : They say America is the land of opportunity. Opportunity for what? For children to run in the dirty streets? - Mr Mousekewitz in An American Tail: Fievel Goes West2013 June 7, Joseph Stiglitz, “Globalisation is about taxes too”, The Guardian Weekly, volume 188, number 26, page 19:  It is time the international community faced the reality: we have an unmanageable, unfair, distortionary global tax regime. […] It is the starving of the public sector which has been pivotal in America no longer being the land of opportunity – with a child's life prospects more dependent on the income and education of its parents than in other advanced countries.