I believe Surtain and Walrus are dead on here an I agree with them. People DO care about defense, but it's typically more of the football purists and those that actually appreciate the game itself and what all it entails. Fans of football, whether it's in my case... professional, college, high school, or Junior Varsity, we come from an era where football is indeed 3 phases... offense, defense, and special teams.
The NFL's insane popularity nowdays generates it's tremendous revenue through various streams and outlets. However, this insane popularity has in turn watered down fanbases. The NFL's popularity reaches a demographic now that doesn't actually understand the game itself. It's all fantasy football driven. NFL fans in general have become for the most part jock sniffers who only want to see skill position players put up huge "fantasy" stats and run out and buy their jersey.
You can't even have a football discussion anymore that isn't centered around statistics unless you're talking to a coach or scout.
Furthermore, you see the extent to which the NFL has watered down it's increased fanbase by trying to appeal to fans on different continents and playing games in Europe. This is where you get into an entirely different dynamic between college fanbases and NFL fanbases. Die hard fans of college football are typically from a little bit older generation, obviously disregarding the current student body and recent alumni that pack college football stadiums every Saturday in the Fall. College football doesn't attempt to appeal to a foreign demographic.... but only it's local fanbases who for the most part, appreciate the game of football itself.
The NFL's attempts at improving player safety has more to do with being more marketable and protecting itself from lawsuits than it actually does about player safety. The inconsistency and selective way they choose to enforce it for the higher profile, and more marketable players that have already been pointed out in this thread are proof of that. The NFL is basically trying to eliminate defense all together for the sake of high scoring shootouts that make it more marketable to the watered down fanbases it's trying to draw in. Fantasy football.
Receivers aren't afraid to go over the middle anymore. A stern look at a $50 million quarterback draws a flag. The NFL had one quarterback in it's history pass for 5,000 yards, now it's the new bench mark for a pro-bowl season. Bill Polian had the rules changed to help Peyton Manning in the playoffs after Ty Law mugged his receivers and picked him off 3 times in a playoff game. That's when the back-to-back-to-back assaults on the league's single season record for TD passes also began.
That flag football game called the pro-bowl that the NFL finally just decided to do away with? That's exactly the type of football you're going to see every Sunday with the way it's headed.
Go watch the beating Tyler Wilson took last September against Alabama. That would never happen in the NFL. A game like that would draw a dozen flags in the NFL. College football allows defense to still be part of the game, because as I mentioned previously, it's still for the football purists who appreciate that defense is still one-third of the game. It's why the high flying gimmick offenses who run up 50 points on their conference opponents every week get shut down every time they face an SEC defense.... the same way elite defenses in the NFL typically always won out against elite offenses.
If player safety is the commissioner's goal, an 18 game schedule is entirely non-sensical.
The NFL has indeed made itself more popular and more marketable, and richer than it's ever been. However, don't mistake that for improving the quality of the product on the field. It's just the opposite.