Here's what I think the problem is...

With the salary cap going up and the players getting so much money with the franchise tag, some have lost their motivation to "settle" for a long term contract.

Look at Trumaine Johnson. Jenkins just got a 62 million, 5 year contract with a 10 million bonus and 28 million guaranteed. Johnson thinks he's as good as Jenkins but he might settle for a little less. But why settle for say, 6 or 7 million a year? He can make twice as much one year under the tag and still get his big contract next year. Of course there's the risk he gets injured and that would have come into play in the old days when he was making, say, a couple of million and year and risking a lifetime income of 20 million. But now, he's getting almost 14 million for one year. For most of America, that's more than they will make in their lifetimes. So where is Johnson's incentive to sign a long term deal? So he gets hurt and never plays again. He's still got the 13 million and most would be set for life. But if he can just make it through the season, there's at least another 50+ million waiting out there from someone. Or another franchise tag.

So Cousins bets on himself and loses, then what happens? Well he's getting almost 20 million this year, again a lifetime of income in one year. Barring a devastating injury, he'll get another contract next year or another 20 million plus tagged again. Let's say he absolutely sucks and they cut him. You don't think some team won't pick him up and invest in him for even a paltry 8-10 million a year for 3 years? With his 20 million this year, he's set. Anything above that is gravy so why not roll the dice? The reward is too huge and the floor not too low.

(And by the way, Cousins and Johnson certainly have insurance, so even if one of them has a career ending injury, he'll still get more money from the insurance company.)

Like the rookie salary cap, it would seem that this will eventually have to change. Otherwise lots of teams will lose their young stars or wreck their salary caps keeping them.