you could also ask why were pro sports all white for decades before they began to look for talent outside that pool? didn't team owners (and local fans) want

you could also ask why were pro sports all white for decades before they began to look for talent outside that pool? didn't team owners (and local fans) want to win games above all else? eventually, yes, winning is what ultimately mattered most - but it took half a century for that priority to be fully recognized as the one that outranked all the others, including racial bias.