It does so every year... teams are much better at managing their caps, and they don't let good players go.
Consider: if Colston was going to hit the FA market, do you think the Saints would let him?
Exactly every team but the Falcons (under McKay), Ravens, and Redskins have done a decent job managing the cap. So they have money to keep their best players. The franchise tag helps them do it. Without the tag teams willing to mortgage their future would end up with all the talent and smaller market teams that prefer to manage their cap would get the scraps. The reason baseball sucks is because unless you're fan of the Yankees or Red Sox you have little to no shot at the Series.
Everyone here would be crying if the owners did away with the cap and negotiations between Colston and Loomis broke down. Yes, right now the franchise tag stinks but it's going to come in handy in the near future.......