> Have you seen _any_ major tech company with close to 50% women or 40% non-hispanic white employees? In engineering roles?

Depends on what you'd consider close. Apple, for example, reports 47% white non-Hispanic employees overall and 44% in engineering. (https://www.apple.com/diversity/) From my personal experience, I've never worked on a team where white people were a majority, although in one case I think the company as a whole was.