Lets talk pay, US tech workers, lets just say Sr SWE and up, and lets look at SF as the author uses this as a focal point. Salary is roughly $300-400k a year(in SF FANGish company), in Europe or England its about half of that, and maybe even less. I know as I have family I married into that points out this fact, the best workers all go over to the US and make large salaries over there at US tech giants.
Lets talk about taxes, especially in the northern European countries taxes are extremely high when you get into professional wage bands, ie. above 120-200K euros(50% tax rates in some countries compared to 37% top US tax rate) and capital gains which is a huge issue as some employees get a majority of their income through this - 30% cap gains tax rate and above for a decent amount of western/northern EU countries, compared to 20% top tax rates for US.
Lastly lets talk about employees, you hire someone and they don't work. In Europe you cannot just term them and give them a severance package of a few weeks. In France you are not allowed to even layoff employees unless you are close to bankruptcy(I think this was changed a few years back). But in general it is very hard to fire employees who are underperforming in the EU.
All of these facts really highlight why alot of top talent and founders from the EU come over to the US to make money and start companies. I am not saying one way is right or wrong but just want to pint out the points that both ICs/managers and founders have all told me(I am US based).