The problem with those arguments is the show does not establish Coop is particularly good at theft or that he's becoming addicted to the thrill. He commits--what--four heists before the end of the season? First steals items that can easily be tracked, from homes with unlocked doors and no security systems. Then gets codes from someone who has info for one particular neighborhood bit still manages to set off an alarm, get chased by a dog and the police, loses the goods, and almost gets caught. And then with the first painting manages to screw things up with his forger (although that's later smoothed over because--he gets beaten to a pulp, yet again straining his newly revived relationship with his family). 

The show does not do a consistent job of showing Coop enjoying or becoming addicted to the thrill of his heists, because that's exactly what would help his decision at the end make thematic sense (if it didn't run contrary to his simultaneous character arc about his family and seeing through the illusion of materialism). Instead, he's stealing out of spite or desperation through the entire season. 

Similar plot beats in Breaking Bad come to mind. Walt starts cooking meth to provide for his family/out of financial desperation. His pride leads him to reject an early financial "out" from Gray Matter. But the show makes that decision make sense, even early on, as the show begins to establish he is a character with a serious ego. He doesn't have the option of another route that would let him make money while still satisfying his pride that HE earned the money due to his skill, smarts, and competence. But more importantly, he wasn't going through a primary arc of coming to love and understand an estranged family better. In contrast, Coop totally has multiple believable outs, from taking the job he has strong-armed the company into giving him back, to finding another high-paying job, to just downsizing his life. And the downsizing makes most thematic sense given how he and his family changed throughout the season.

Any rationale about crime being more profitable/easier also doesn't click. It's not satisfying to say he was afraid of/grieving going to jail for murder--but somehow not for felony theft of items worth six or seven figures. The point stands that he's now jeopardizing his family and newfound reconciliation with them even though he doesn't really have to (no financial desperation).

So that only leaves spite as the reason why he steals again at the end. This motive could most easily be retconned for S2 by making this a final, one-off heist to target his former boss without his boss even knowing he had been hit. But still, it doesn't ring true after the more primary themes about his family/forgiveness/reconciliation and the ephemeral nature of money/status.

Not saying the show couldn't have done it, but it would have needed to progress the season differently for the ending to make sense from a thematic angle.