Why do Teams wait so long to get rid of players?

they could have had Randy Moss with a draft pick, but they ped on him. Jerry Jones has always been a risk taker. You never know how things will work out, intil you put the players together. he spent too much money on to to release him, without much thought and conversation. still gonna cost us 9 million dollars toward salary cap. so, he is still causing trouble, and not even here. he was good, but caused too much stink.