The original post assumes the players all remain healthy and a playing at an appropriate level. I stole a bit from Darrell Royal** but three things can happen when signing a player to a multiyear contract and two of them are bad; the player can meet/exceed expectations, fail to play to the level of the contract, or suffer an injury (injuries) that make the contract a cap burden. The third of these is especially detrimental as a team then needs to spend additional money for a replacement player. Most teams try to structure contracts to have an out after year two and the option to kick money into future years by using roster bonuses that can be converted to a signing bonus and divided out over the remaining years of a contract.

** Darrell Royal (60s Texas Longhorns coach) " I’ve always felt that three things can happen to you whenever you throw the football, and two of them are bad. You can catch the ball, you can throw it incomplete, or have it intercepted."