I think that it's not necessarily whether someone is born into wealth or not. Yes, some people are born with a silver spoon and didn't put much effort to be wealthy cause someone else has already paid the price but the truth of the matter is that the person would still have to put in work, may not necessarily be working too hard but and effort must be made to manage the wealth and make sure they don't go broke due to lavish lifestyle for instance they'll have to discipline themselves and avoid certain things that would drain their wealth. Being disciplined is not really an easy task, it requires self control and determination, if it were easy, there won't be people who leave lavish lifestyle and squander wealth already made for them. Making wealth is not easy and I really appreciate those out there who work hard against all odds and acquired wealth by themselves.
It does not mean that those who work hard cannot be successful because even though we are born from ordinary families, when we work hard, we will definitely get a momentum or a path to achieve success, it's just that in this case the road will be much steeper than those who have the privilege and benefits of being born into a rich family.
Indeed it cannot be a benchmark because in the end we cannot choose where or which group we are born into but in the end when talking about success then surely this will have a different impact considering that people born into rich families will always be superior from the start when compared to poor families in any case including in terms of success and privilege.