Why is the National Anthem played at Sporting Events ?

The song was played in 1862 at at Baseball game according to our history records here in America. It became even more popular as it was played during World War 1 in 1918.

The song was mostly played at larger events like the World Series due to many owners could not afford the bands to play the song at all sporting events up to around World War 2 when sound systems began to be developed.

Around when World War 2 happened the National Anthem was played just about everywhere according to recorded history. Some teams and sports stopped playing the song after the war but than around 1967 during the Vietnam War the song was played at all most all sporting events and has never stopped.

HERE ARE MY QUESTIONS:

Could the solution be only playing the song at larger events like the World Series, Superbowl or Championship games in sports ?

Can other songs be played at these sporting events?

Is there a better solution to be found about the Song and standing or kneeling during playing the song?

Is there a debate on if this crosses the FIRST AMENDMENT ?

Does the President have the right to tell sporting leagues and industry they have to play the song and that players have to stand during the song?

How come we have heard nothing about the fans at these games what did they do?

In closing I neither agree or disagree with President Donald Trump or the sporting industry but this has opened up a lot of social media, and news for the moment!