When the NFL pulls in the green like it does, the owners can be far more willing to compromise unlike, say, the NHL where a lot less money is in the offing.

Not to mention that NFL contracts aren't guaranteed.  For example Shaun Alexander's vaunted new "highest paid RB in history 62 million, 8 year deal" is in reality only 15 mil guaranteed and likely he will be cut in 3 or 4 years after making half the total contract.  There are a heck of a lot of medicore NBA centers and MLB LFers making 8-10 mil a year for several guaranteed years.

Of all the major sports the NFL players probably have the worst deal.

Historically, NFLPA has been really weak.  But no more.  Al is totally correct that the share of revenue going to wages is the best way to measure success and they were successful.

The players union had a very strong hand to play.  The league is booming, laying golden eggs.  And if the owners locked players out illegally the NFLPA had recourse that baseball players don't have because of the antitrust exemption in baseball.  I don't think a players league or WFL/AFL redux would necessarily get off the ground, but it changes the dynamics for the owners. 

In addition the atmospherics are better for NFLPA. The players don't have the same steroid issues as baseball. The last big labor dispute happened two decades ago and doesn't have the bitterness associated with it that baseball does, in part because palyers in football are physically brutalized as part of work and baseball player eat sunflower seeds. That dynamic makes football players wanting a larger piece of the pie seem much easier to justify.  Also, the replacement players were a joke, keanu not withstanding. 

Owners in both leagues, if left to their own devices might generally have anti union instincts.  But it means different things in baseball than in football.  The owners in football have done a better job in sharing prosperity.  Its almost socialistic.  That means they all have an equal stake in having the season continue.  Not so for the Royals versus say the Mets or Yankees in baseball.  Those economic divisions mean that there will always be a more militant edge to the most confrontational owners in baseball than in football.  This leads to leverage in a mad bomber kind of way.  Moreover the inability of owners in baseball to fix their underlying economics has increased the stakes for the owners at the bargaining table. 

Is the guaranteed contract in baseball a better thing? Yes.  But even if one player loses money becasue he's cut, each year that 60 percent of revenue is being split up some way among the players.