Key word being "Fairly new". Most chicks in pr0n eventually do it if they want to stay relevant. Alexis Texas and Rachel Starr are pretty much exceptions to the rule as far as I'm concerned and I don't see them working much these days especially Alexis.
the chicks I have in mind have 3-4 years under their belt and probably around 40 scenes at least and they're pretty much in the top 10-20 of any big pr0n site you go to. I would say they're pretty relevant. Even after that I have ones in mind that have been in the game 7+ years and are also top tier with no interracial scenes.
Most chicks do interracial nowadays but like I said there's still a handful of top tier ones that don't. I really doubt it's hurting them , why would it ?? If Alexis Texas was able to stay relevant her whole career and be a top tier pr0n star with no t*ts and that awful gap in her teeth then I dont see why other decent looking pr0n stars couldn't do the same. Black people still watch Alexis Texas either way.