We'd generally be better off if everyone was given growth opportunities; that's just a restatement of the idea of human capital.
Not sure if utilitarian or humanitarian is the better metric, or if there is a real choice. The article does not seem to address the downsides to high prospect/low achievers.
As far as I can tell, we in the US have more resources devoted to creating environments where equality is tested in only in material status, and to transcend this fairly prescribed order is to risk ostracism.
It is not self-evident that giving growth opportunities to "talented" individuals maximizes ROI, as opposed to least privileged, for example.