The biggest difference between a 4.5 rated player and a 5.0 is probably patience in kitchen rallies. The lesser player will try to put something away that the 5.0 player will simply dink back defensively. What the 4.5 player doesn’t really understand yet, is that when facing two good opponents, it is like facing an invincible wall. Anything the 4.5 player tries to force out of a quiet and soft kitchen rally will come back twice as fast and hard. Many of the really top players will simply wait, and wait, and wait some more, until the opponent makes a mistake big enough to capitalize on. Or, another way of looking at it is that the lesser player will try to leverage anything that has possibilities, where the more experienced player will wait until s/he has a sure thing.
Now, you might have wanted to have these long soft rallies in the kitchen when playing with less-than-5.0 players and it didn’t work. That’s because you and your partner are probably not a wall yet. Furthermore, unless you are playing with top opponents, they are the same as you, and are thinking they can take advantage of anything that’s close to usable, trying for a forehand power shot, or an extreme diagonal, instead of waiting. So, in a typical 4.0 game, whereas everyone knows that there’s a lot of fun in kitchen rallies, such rallies don’t last very long. After perhaps three or four shots back and forth, someone tries to force the issue, and the rally ends quickly.
When you see a high-quality game with long kitchen rallies, it is not that the players are trying to keep the rally soft and long. Instead, they are simply thinking that they haven’t yet received anything that’s safe to try to put away.