The critical reason why Son Heung-min had to join a big club

‌If you fail at teams like Man Utd, Man City, Arsenal, or Chelsea, you can move to teams like Tottenham or Villa.
But if you fail at Tottenham or Villa, you have to go to the Bundesliga.
This is the difference in team class.
Look at Lee Kang-in; he wasn't having a standout performance at PSG, but he's at Atletico.
Ultimately, the prestige of the team name is what remains for future generations.
Park Ji-sung, Lee Kang-in, Kim Min-jae, Cha Bum-kun