Watch this video, these guys catch a BABY that is already stressed and tired. Look at the power he still has! If someone managed to find a way to "boat flip" a big one, it would probably break the back of the boat into pieces and sink it.
https://www.youtube.com/watch?v=3Ker1KtZgyY
I have caught small blackfin up to 12lbs, and been a witness to 40-50lb class yellowfin being landed. I can't even begin to wrap my head around the idea of a 500-1000lb plus version of one of those.
I caught a 51lb cobia a few years back, and when we gaffed and brought it in the boat, my friend got slapped in the leg by the fish's tail. The bruise looked like someone hit him with a baseball bat, and that was a tired fish.
You can't handle a big saltwater fish like largemouth, no matter what tackle you have, it just can't be done.