Renato Canova wrote:
Therefore, in these kind of sports players don't change nationality, because don't have any advantage to do this.
Actually, they do. For example, if they come from a country that couldn't qualify for the Euro or the Worlds, they change to a country that does (normally) qualify.
Or they switch nationality if they aren't good enough for their original country, but would play for a weaker nation.
See for example here:
https://www.thesun.co.uk/sport/football/1259132/euro-2016-83-players-born-abroad-raheem-sterling-roman-neustadter-neil-ashton-column/"Of the 24 teams at Euro 2016, a staggering 83 players — 15 per cent — have planted a flag of convenience in another country."