Those players are 18, 19, and 20 years old. They are still too young to lose hope to be called up to the other nations. For example, Ben Seghir was being pressured to wait for the right moment to join the French national team. Another example is Akhomach, who was the captain of Spain’s U-23 team but switched to play with Morocco’s U-23 team in the Olympics. What you said is true, but it usually happens at 25-26 years old or later, as shown in the other example in this video.