The proposed collective bargaining agreement that could very well go into place in the coming weeks includes something that designates an 18-game schedule as a "negotiable item." With its inclusion in the CBA, owners and players could revisit the debate at a later time before the agreement expires. It's clear that an 18-game season isn't going to happen in the next couple years, but the owners don't want to completely forget about it in the future.
The thing is, based on the wording that came out, the idea of playing 18 regular season games has basically been eliminated altogether. With it simply being something that can be negotiated, the players will be under no pressure to change their minds and extend the regular season, meaning this issue is essentially dead, as Mike Freeman writes.
The players despise the idea of an 18-game season so much it's likely we may not see one in the next 10 to 20 years if ever. Players see it as a symbol of owner greed and a detriment to their very lives as football players. They view the 18 games as a generator of more concussive brain damage and overall bodily harm.
Players, rightfully so, don't think the extra headaches (literally) are worth the extra revenue. This is why they've fought so hard against it and didn't budge during these negotiations.
Obviously you never want to completely write off the idea of an 18-game season because someday a different set of owners could make it more feasible with providing more concessions or technology could lessen the impact on players' bodies. In the next decade, however, it appears the regular season will be staying at 16 games, and that is definitely a good thing.