The NFL has four preseason games on top of its 16 games long regular-season schedule. The NFL has a voluntary mini camp, offseason team activity, mandatory mini camp and training camp. Teams even have joint practices with other franchises to measure where they stand against their peers in a controlled situation to avoid injuries. These are far more productive than preseason NFL games, where starters play less than a quarter in one of the four games.
The reasoning for the lack of play by starters is because of the injury risk, so what kind of message does that send to the rest of your organization by putting them out there? That their injury would be not as detrimental to the team? That they aren't as important to the team? That they might not be in the team's plans for the future at all? That they are dispensable and just not as talented as the rest of the roster?
Would you want to risk your body and your future in such a dangerous situation if this was the way your employer treated you? I wouldn't.
On top of the poor product that is put out on the field, season ticket holders are required to purchase tickets to the preseason games as well. The tickets are sold at the same premium price as the regular season tickets, but for a far inferior product.
The NFL is the only form of football that consists of these games. College football has a "spring game" that occurs months before the season and allows for rest and rehabilitation for the entire roster. High School football doesn't require it. Arena football, Canadian Football, the XFL, and the AAF all did not hold these games.
Why would the most talented league of football players in all of the world be the only league that requires this?
The only possible explanation for these games is that the owners of the 32 NFL Franchises are too greedy to give up revenue to ensure the health and safety of their organization's players.
It is very important for the NFLPA to negotiate for a balance of power between the owners and the players because they have been taken advantage of and been mistreated for far too long.