The football population of Vietnamese football has already surpassed the football population of Chinese football in 2010, and Thailand is even earlier, why have the national teams of Vietnam and Thailand not reached the top level in Asia in terms of results and level like the national teams of Japan and South Korea?
The general rule of football is that high-level league × football population = national team results. The U.S. has twice as many registered players as Germany, but the fundamental reason why the U.S. team is not as good as the German team is that the U.S. top league is not as good as the Bundesliga.
The level and results of the Vietnamese team and the Thai team are not as good as the Japanese team and the South Korean team, and the main reason is that the level of their top league is not as good as the Japanese league and the Korean league. If the level of the Vietnamese league and the Thai league increases significantly, they will also be an obstacle that will be difficult for the national football team to overcome.
It's very simple to follow the laws of football. It's a pity that the Football Association doesn't understand, and neither do the fans and the media.