I think the GP's point still stands. Smart companies will have an advantage recruiting these engineers, because they have less competition, and so they will win. (Corollary: the quality of the team is the strongest predictor of success).
I agree. Anyone who would hire a worse employee because they don't like the other's {race,color,nationality,gender,sexual preference,...} is an idiot, and I wouldn't bet on their success.
That said, we definitely need some short term solutions too. "Evolution" isn't particularly helpful to those being discriminated against right now.
The lack of women or black people in engineering isn't proof for their discrimination though. It could be that they simply choose to pursue different professions because their upbringing is different.
It's more complicated than that. Substitute legal framework with 'cultural normative behaviour' and we end up at a different position.
I just highly doubt there's a lack of women or black people physically capable of being engineers.