There is no right back in world football who can influence a game from that position better than Trent does.
There are very few players in any position in world football who have his passing range and vision.
There is no-one at the club who is equally comfortable making a pass or taking a shot with his weaker foot (bug-bear of mine).
He is young, has a good injury record and is highly marketable.
Yes, he's not the best defender (but he's better than he gets credit for) and he doesn't have the skillset to dictate the tempo of a game the way someone like Kroos does, for example. So his impact on the game, though often devastating, is sporadic rather than controlling. But we have players in the middle who can set the tempo.
And that's before we get to preserving his re-sale value rather than letting him leave on a free in his peak years.
We should absolutely push the boat out to get him to renew, but I think he is realistic enough to understand that a right-back won't be the club's top earner and I don't think we'll need to go that far.