I think this is true for most anthems. They are way too long to play completely. I do think it would be a funny thing if they would. Past the first portion, only the people who were hired to sing the song would still be singing.
I wonder what the shortest anthem is? Brevity is king!
Here's a link to the Ugandan Anthem it sounds joyful and the lyrics are nice: Oh Uganda! may God uphold thee,
We lay our future in thy hand.
United, free,
For liberty
Together we'll always stand.
Oh Uganda! the land of freedom.
Our love and labour we give,
And with neighbours all
At our country's call
In peace and friendship we'll live.
Oh Uganda! the land that feeds us
By sun and fertile soil grown.
For our own dear land,
We'll always stand:
The Pearl of Africa's Crown.