1. More demand than offers of high-wage jobs are not a cause for reducing these wages.
This would not be the case if wage inequality came mainly from a price adjustment between demand and supply of employment. Explicit and implicit demands for high-wage jobs are always more numerous than offers, without this being a cause of reducing the gap between high and lower wages.
2. In other words, there is a shortage of managers and other employees who speak, read and write fluently in both good French and Russian.
As long as this shortage lasts, it can be expected that managers and employees who have this qualification will tend to be paid more than their counterparts who speak, read, and write fluently in only one of these languages. If such a case arises, it is one of those in which wage inequalities have as their complementary cause an adjustment by the price of supply to the demand for employment.
3. In other words, good salespeople and good accountants who are also paid.
Suppose that the recruitment of a good salesman becomes more difficult than that of a good accountant and that this circumstance puts an end to the previous equal pay. This case is also one of those that shows that wage inequalities have as a complementary cause an adjustment by the price of supply to the demand for employment.
4. The existence of a common performance for all jobs is imaginary.
Mentioning the productivity of labor can give the illusion of this. But this is a verbal set-up and not a reality. Within a firm, turnover or value added per person employed is a quotient that lends itself, albeit within relatively narrow limits, to meaningful inter-firm comparisons. However, it is not an average around which the "productivity" specific to each person employed would be dispersed. In addition, there are the following two. Not all employers are enterprises, far from it. For many professions, there are no economic returns per person employed: justice, police, army, education, among others.