The Thunder paid a small snippet of the tax last season, putting one year on the tally. Two more in the next three years, and they're heading for the dreaded repeater. Re-signing Kanter virtually guarantees Year 2 of it. And if everything goes according to plan and Durant re-signs, it will require some salary cap gymnastics to get under it before Westbrook is due for his new contract in 2017. But it's going to be possible to do, because again, the salary cap is going to go bonkers.
So this is the important takeaway: Had the Thunder gone all-in in 2012, instead of adding pieces now, they would be looking to begin a tear down, which isn't what you want to be doing when you've got to re-sign Durant. That's why Kanter's max today isn't comparable to the one the Thunder wouldn't give Harden in 2012. It wasn't just four offseasons ago, it was four salary caps ago, too. That was then, this is now.