I see it more focused on a question of salary, the higher the salary of a player, usually the higher the percentage of trade of club products, if you add then ranking of points, rebounds, etc. improves, but usually the players with higher salary, get higher % of sales.
Players from the micronations, apart from some exceptions, tend to have a much lower salary than those from a bigger nation, such as France, Spain, Germany...they are used more for a relatively quick entry into the national team and to do business with them, not in their real training, a solution to this problem would be that the players of these nations, we bet more on national players and their improvement, but it is something that is not seen too much, many of us, we prefer to be competitive in the short term and sign players from other countries, perhaps therein lies a large part of the problem.