On thing is to be comfortable with being the 6th man your entire career (a la Manu) and another is recognizing a healthy enviroment in which one can thrive in his rookie year, or even in his entire rookie contract. If he (or his agent) kept pushing for more money is because he felt he deserved it, and if he felt he deserved "max" money is because he envisions himself as something much bigger than a 6th man. Maybe I'm wrong, but I'm just reading between the lines here. Nobody is willing to pay the max to someone who comes off the bench, maybe it was some kind of pushing OKC to move him to the starting lineup.
As stated also in the article, he wanted a fifth year which OKC couldn't offer (because Westbrook and Durant already have one and they couldn't offer another one) and a guarantee that he wouldn't be seemed as a great trading chip (like Rondo's contract: "max" player with a friendlier contract) or that he wouldn't be traded to a crappy team.
All in all, that seems TO ME as he wasn't all that comfortable with what OKC was offering as a whole.
Wait, but that actually contradicts a bunch of things actually stated in the article. I'm reading it differently. Harden didn't really need the max -- Simmons spent quite a bit of the article talking about how it came down to the trade clause AT the $54M price. If Harden was going to take a discount (which he seemed willing to do), he wanted a no trade clause to go along with it so that he couldn't take the discount and then have Presti move him to some other team a yr later. Presti said no to that, and that made Harden much more suspicious.
By negotiating w/ the Thunder instead of other teams, as Simmons noted, Harden was already showing a willingness to take a discount -- otherwise, he knew from the start that OKC could not possibly give him as much money as another team could and would. It never said Harden necessarily wanted a 5th yr; it was proving the point that had he wanted it, he could have chosen to go elsewhere from the start since he knew from the beginning OKC could not physically offer it. Why even negotiate and set a price where he'd agree then in the first place?
Harden indeed did want a no trade clause. He did not want to become the next Rondo after being suckered into taking a discount. I think that is very fair. Either make him take a discount ($54M) and give him his no trade clause, or give him the $60M he's asking for at the 4 yr max, which is already Harden being willing to forego the 5th yr to stay w/ OKC. Presti chose to do neither, so thus, Harden of course was uncomfortable w/ what was left on the table. If Presti gave him one or the other, I think Harden would have been plenty happy staying in the 6th man role (which he himself said in interviews after coming to Houston that he would have been perfectly happy in).
And 'max' money for a bench player is perspective. He'd initially still be costing the organization less than the old Manu would haha.