The real reason is that almost all FAANG category companies and a big number of VC backed startups are HQed in USA and most new projects/development happens the

The real reason is that almost all FAANG category companies and a big number of VC backed startups are HQed in USA and most new projects/development happens there so they have to attract top talent. The next question is why US attracts almost all VC funding and the reason is that it has the most people or other companies that are willing to pay good money for B2C or B2B software. The other question is almost all FAANGs if any start/continue in US. Many starts outside but once they grow bigger they legally move to US. I think the reason is the US First Amendment, favourable copyright, patent, tax laws etc. Facebook and other social media would have faced a tough time (probably shut down) even in many western countries even as they lack an equivalent of First Amendment. Now it is the networking effect, US FAANGs earn so much profit that $0.5m developer salaries are a dot in their balance sheet. They are setting the benchmark and it is almost impossible for a company in rest on the world to match it in their home countries.