i think your friends, network and environment dictates the kind of success you have. the things you mentioned, going to good schools, getting into a career with plenty of successful people around you, begets that kind of success.
but i also know a handful of folks with success that did not go to good schools or have great careers but achieved significant business success: an oil rig machine parts manufacturer, a fabric mill owner, a latex manufacturer, a luxury furniture reseller, that have achieved success because their friends and networks are the kind of guys who will keep having goes at different businesses and products until something sticks. most of these businesses aren't cutting edge technology but there is a lot of value in unifying supply chains that are still very dependent on trust and know-whos, as well as having a bit of edge in the business negotiation process. their success had little to do with which schools they went to, only that they surrounded themselves with other people who made business their focus.
but i also know a handful of folks with success that did not go to good schools or have great careers but achieved significant business success: an oil rig machine parts manufacturer, a fabric mill owner, a latex manufacturer, a luxury furniture reseller, that have achieved success because their friends and networks are the kind of guys who will keep having goes at different businesses and products until something sticks. most of these businesses aren't cutting edge technology but there is a lot of value in unifying supply chains that are still very dependent on trust and know-whos, as well as having a bit of edge in the business negotiation process. their success had little to do with which schools they went to, only that they surrounded themselves with other people who made business their focus.