Five-ten minutes? Do they play all four verses?
About half of that is getting the band and/or singer ready - it's logistical. Get the band in their seats, get the kids attention - the typical non-sense you see and expect to see by a bunch of high school kids prior to doing ANYTHING. The sports game really doesn't start until moments after the national anthem, right? So, getting the teams, the band and the announcers all coordinated - takes at least 3 minutes. The anthem itself is about 2 minutes; and the game usually starts about a minute AFTER the anthem has ended. This time adds up - and when you are playing at a rented arena, every minute has some dollars attached to it.
No way. Fourth verse would be "illegal" on public school property.
Oh! thus be it ever, when freemen shall stand
Between their loved home and the war's desolation!
Blest with victory and peace, may the heav'n rescued land
Praise the Power that hath made and preserved us a nation.
Then conquer we must, when our cause it is just,
And this be our motto: "In God is our trust."
And the star-spangled banner in triumph shall wave
O'er the land of the free and the home of the brave!