That's blatantly not the issue, as supported by the actual facts of the global economy.
The French have seen their wages grow at 1/4 to 1/2 the typical rate of American wage growth for the last decade. They do not lack for collective bargaining.
The American median wage is higher than the German median wage. The Germans do not lack for collective bargaining.
The American economy and median wage has outperformed: France, Germany, Spain, Italy, Finland, Britain, among many other developed nations.
The American median wage is also higher than: Sweden, Finland, Netherlands, Germany, France.
The American median wage is so high, nations such as Britain barely qualify as matching up with our poorest states.
Wages aren't everything. Many of these countries actually provide stuff for taxes. Living in Norway, I can go to school for a nominal amount. Health care is included in taxes, and doctor's office visits are reasonably priced. Folks working at low-paying jobs tend to be much better off, plus there is an actual safety net. Public transportation is vastly better overall.
There is a strong union presence here - both for normal employees and management. There are also actual laws to protect workers. This includes things like paid vacation, paid time off if you are sick (more if you have children), paid leave after having children (some of which can be split between the parents). Everyone is entitled to a job contract - even for temp jobs or fast food workers. Not all of the costs for the benefits is paid for by the employers: Healthcare is a tax, vacation pay is withheld from the employee's wages and paid the next year, and the government (taxes) pay for sick or parental leave.
Nope, it isn't perfect, but it surely isn't representative of the picture you paint because the one you paint leaves out the quality of life stuff.
All of those countries have cheap or free higher education and healthcare. Perhaps they don't need wages as high since their government chooses to cover two of the largest expenses an average person will encounter in their lives.
But by banding together, and pooling the money from the average and the very wealthy, most people are able to get education and services that they would otherwise be unable to afford.
I'm pretty sure that not only does this guy have no sources, but is outright wrong in the case of Germans.
The American Salary is higher that Germans, but Germans also work less hours on average (with higher productivity mind you, but that's not important at the moment). It actually comes out to Germans having a better median wage.
Comparing the gross salaries of employees between countries is meaningless. You are e.g. comparing after employer taxes, which have large differences between countries.
To meaningfully compare countries you need to either compare the gross wage costs per employee that a company actually faces or compare the net income of employees after all taxes. And correct for purchasing power of course.
Which has exactly the same sort of problem. If a government reduces employer taxes and increases employee taxes, you have a magical free gross wage growth.
You can't make incomparable values comparable by reducing them to a ratio, except in special cases.
