Because the talent the US attracts started learning English before they came to the US. English is the lingua franca of global communication and is taught in almost every country. The same cannot be said of Chinese.
1. You are usually effective and comfortable in the language you were educated in.
2. If you want to do business with a person in another language, you usually both default to English because it is usually second language if it is not their first.
I mean look at your own situation. I assume that you are fairly well educated (on Hacker News, decent grammar, and asked a good question). Suppose you had to leave the US, where would you go?
Your top choices might be other English speaking countries (Ireland, Canada, the UK, Australia, New Zealand).
Your next set of choices would be places you could do business in English (Berlin perhaps).
Globally, a lot more educated people know English than Chinese. Its not impossible but it is a far larger barrier to entry than, say, blocking youTube.
After Ireland, Canada, UK, Australia, NZ, I'd probably go for Scandinavian countries and Iceland. They have smaller native-speaking populations, a high level of exposure to English, and great foreign language training. Then I'd probably go for countries like Latvia, Romania, etc.
I'd consider Germany and France to be third-tier in that sense because they have large native-speaking populations and a greater expectation that people know their language.
I agreed with you about English vs Mandarin from education perspect and business trade perspect.
What I am saying is that China attracts talent who live in China and why don't communicate with others in Mandarin? Learn Mandarin isn't a binary choose for these talents who live in China -- they can still learn stuffs in English and do business with other people around world in English.
From my experience that learn English is not only about helping me to communicate with others, but also, help me to learn a different mindset and culture.
Because up until very recently, very few people outside of China that were not ethnic Han spoke Chinese.
The concept of "Chinese" is fairly inaccurate anyways. I'd like to flatter myself that my mandarin is ok (I won't starve and I generally can make myself understood) but I can't understand most Cantonese. Cantonese is classified as a dialect of Mandarin, but it's really not mutually intelligible.
Whether we like it or not, English is the defacto "business" language. Most (if not all) places in the world conduct business in their native languages(s) and English.
So why would I want to learn Mandarin, which I've been told is super hard to learn and is for most purposes, useless elsewhere in the world?
Following the Second World War, but even before, there was massive world-wide investment in instruction in English; and it has worked its way into the infrastructure. Air traffic control is in English -- and in feet and knots -- all over the world, for example.
Centuries ago, the same thing happened with Chinese; and that is why a Chinese can visit Tokyo and find their way around the train station without knowing any Japanese. Maybe it can happen with Chinese again. Many Asian people learn a little Chinese; and more western people learn it now, too.