Because 95% of those people work with Linux, but not in it. OS X is BSD-based but close enough to make developing or supporting Linux machines simple. My entire infrastructure, thousands of servers, are all Linux, but most of the time I’m working on my Windows PC, and only occasionally do I break out my Macbook or Linux laptop. Love Linux, can’t stand Apple, and I’m meh about MS except for gaming, but Linux as a desktop/workstation OS is still years behind OS X and Windows in ease of use. That said, I do not nor would I ever run either of those in any production capacity, just Linux.
China has high speed rail in its eastern most populated section, with a single line running to the entire western half of the country, and similarly sparse lines to the north. The dense population centers in the US are not all in one area, they are spread across the continent interspersed with large swaths of rural land. That being said the US is working on high speed rail, and we’ve had passenger trains that cross the entire country for nearly two centuries - see Amtrak, as well as bus services like Greyhound.
As much as I hate to break up a circle jerk, the US is about as good at this as any other western country, and it’s doing it across an entire sparsely populated continent, not small, highly dense European countries.