The qoute is saying that even if we all have equal ability to achieve an oppurtunity, for instance, the oppurtunity to attend college, we still won't be equal because we won't all have the capabilities for that college to accept us such as access to good highschool education to prepare me for that college or money to pay for tuition.
To give an example a white male and a black male both have the opportunity to send a letter in the mail to apply for college but when the letters come back we find that only the white male gets in because the black male doesn't have the money to attend and because he went to a worse highschool getting a worse education than the white male because the white male lived in a better area.
This quote is referring to the major race and class inequality in the world its specifically highlighting the inequalities in access to skill acquisition or "capabilities"
:) I hope this helps good luck!! Questions are welcome
