Your second point is the main reason. A company that can generate more revenue by hiring more devs is incentivized to hire more devs. [1] As an investor this is

Your second point is the main reason. A company that can generate more revenue by hiring more devs is incentivized to hire more devs. [1] As an investor this is a no-brainer. There are plenty of US companies that hire devs that do not have these economics, but they’re forced to pay more or loose the few developers they have. What reduces the upside of European companies hiring? [1] Calculate the revenue per employee of Facebook, Apple, Google etc to see how much money is involved.