> my point is that the absolute worst-case scenario for the original commenter is still miles better

So we shouldn't worry about something bad because worse has happened before?

> The worst-case scenario in OP's book is that China joins the ranks of first world countries, which then go from being 100% white to 90%.

You're making things up again. OP described living in a China-centric world, not one of equals. (Also your population statistics are _way_ off. 100% to 90%? The population of China is comparable to every other western country combined.)

> Worst case, he might miss out on one business deal because it was struck in Mandarin

Worst case, he might be actively discriminated against and passed over because in spite of investing considerable time in mastering Mandarin he's not Han.