I think this speaks for itself as too why I found you dismissive.whatever about her personal popularity within the African-American community.
Once again, Halle Berry was a big draw to the X-Men due to her popularity in the African-American community, which in turn drew in a larger crowd due to her appeal to that audience.
If it's all about green as you say, then FOX studios did their homework by considering that. Thus pulling in a community that normally isn't drawn heavily to sci-fi/fantasy type films. In turn making more money for the X-Men film franchiese.
Exodus, it was not my intention to be dismissive of your community and I apologise if that's how that sentence seemed. I don't think it should be read that way when taken in context of the rest of my post but if it did, I'm sorry. But my point is, whatever her popularity as a person and an icon within that community, it doesn't appear to have been reflected in the box office takings of her pre X-Men movies. Not one of them was a substantial hit, apart from The Flintstones (and she only got that role when the original choice of Sharon Stone pulled out) and Executive Decision, which was hardly 'A Halle Berry movie.'
Indeed, by your rationale, Catwoman, which was the first time a black woman played the lead in a solo superhero movie, should have been a big hit, but it was a flop. So much for appealing to a larger than usual crowd.
The fact remains that the X-Men script always featured a black female character in Storm. Storm was always going to be played by a black actress, most likely an African-American one. Did it really have to be Halle Berry before the African-American community got interested in the movie? I genuinely don't think that HB would have proved any bigger a draw than, say, Angela Bassett, who at that stage was a more proven leading lady and had an Oscar nomination under her belt for playing Tina Turner (herself an iconic figure) or the pop star Brandy, who was also highly mooted in the rumour mill at the time of casting. Berry was much less known than them. I've no reason to doubt that she would have gotten more attention than a complete unknown but she was not a box office draw in the way that Julia Roberts or Sandra Bullock would have been in 2000.
You also may be giving too much credit to Fox in the way that the movie was cast. Fox had very little interest in this movie and was totally unsupportive of it, being rather surprised when it proved a hit. Halle was cast by Bryan Singer, not Fox executives. To be fair to Singer, I think he has always cast who he believes to be best in a role, not who will be the biggest box office draw or who will appeal to what demographic. Hence we got an unknown Wolverine and an unknown Superman in his movies. Do you think he was going 'Right, I'll get Ian McKellen in to attract the gays, Patrick Stewart to pull in the bald community (to quote Larry David), Famke Janssen & Rebecca Romjin to sell it in Holland and Tyler Mane to get the mullet-wearers'? Nope. He liked Halle for Storm. End of.