Why would the audience be given copies of the speech beforehand? It doesn’t look that good on TV to have a great number of those present with their heads down rather than looking at the speaker.
The answer is simple.
A large number of those in attendance are old and hard of hearing. There's nothing worse than getting repeatedly interrupted by elderly lawmakers yelling into a neighbor's ear asking, "hey man, what’d he say?”
The solution is also simple.
Term limits!