Yup. think of all the mainstream black actresses under 40 and not many who get steady/top 3 billing work immediately come to mind without google. zendaya (disney kid), zoe (celebrity daughter), zaza, tenoyah, lashana? alexandra shipp i guess? and most of these are biracial/light skin.
The industry is nasty work. I recall it was cited on here that even Michael B was about to retire from acting before Fruitvalle Station happened because he just wasn't finding steady work. Hell, Danai Gurira (45) is pop culture certified twice over (TWD, BP), yet how often do we see her. It is what it is.