Pelosi's reasons here are very specific - she's looking at the business end of a losing argument and its not in her interests to give Trump the floor.
Although I wouldn't disagree with doing away with SOU entirely you know the rats will never pass up the opportunity when they have the WH back.
@skeeter I wonder if traction could be gained for a Constitutional amendment requiring nothing further of the state of the union than a written message to Congress. (I wonder if anyone in position to do so would have the cojones to do it. Let's face it: Damnocrats
and Republicants alike love it when a president from their party deigns to grace Crapola Hill with his presence for a windbag speech.) Let a president---
any president---rant his or her fool head off in a written State of the Union address. Then just send it to Congress, which should consider itself unobligated to do anything more than accept it. (The proposed amendment should include a line barring any senator or representative from reading the screed aloud on the floor, just in case.
)