It's as it is because the system imo is broke.
There's no concept of players turning down extensions as far as I can see, so you don't get players running down contracts to test the market.
This is not entirely true - but I'm still trying to find the balance.
Each player will renegotiate for a deal that is acceptable relative to how their skills line up with other players in the league and their contracts. Players don't turn down contracts, but they might be asking you for more than you can realistically give them. If you have a plethora of 80's and 90's on your roster, as they renegotiate you should begin to have to let some of them go, because you can't spare the cap space. This is why players test the market in real life - because they see someone else who they think they are as good as but is making more money than they are.
Unfortunately, tweaks in this area take several seasons to see the full effect of, because current contracts have to expire to see the full impact of them. Early on in development, it was too strong - you couldn't keep any good players. Since the game officially launched, it has been too lax. It has been pumped back up a little since the first of this year. Huge overpaying contracts by teams _will_ impact this, just as it does in real life. In other words, I don't have a salary that a QB should request, he actually is looking at all the other quarterbacks in the league and making his request based on their salaries, it is completely market driven.
I also have on the docket to introduce an opinion that a player has of a GM - and if he feels that he should be on the field and is not, or isn't high enough on the depth chart for his liking, he will not renegotiate. But that's a little bit down the road.