More importantly, rooks are worth less in the beginning of the game (so many pieces clutter the board limiting movement) and in general rooks become worth a little more every time pawns are traded off the board.
The standard values (such as 5 for a rook) are more like the typical endgame potential... in other words a typical active rook in an endgame is worth 5. It could be worth a lot more if it's checkmating, or a lot less if it's stuck defending, but in most endgames it will beat a minor piece, and lose to a queen. That's the basic idea.
So when you're not in a technical endgame, instead of thinking in terms of "this rook is 5, this bishop is 3" it's better to think in terms of which pieces are active (activity being some combination of general mobility and being in contact with weaknesses like pawns or kings). So it's more like this rook is a 5 if the game lasts a long time, so I can either wait it out, or in the short term I might sacrifice it because right now it's more like a 2 and their knight is a 6
Are rooks worth 4.5 or 5 points? Classically, rooks have been considered to be worth 5 points, but modern European chess theory considers the rook worth only 4.5 points. Which is correct?