He Learnt From It And As He Says - Tumblr Posts
Kaz Isn't Actually Motivated By Greed
Or at least, not primarily. Don't get me wrong, his stated primary driving factor is getting the money he was promised from Van Eck, but his reasoning isn't actually greed-based. Kaz's desire for money is goal-oriented and his fixation on it during the duology is fairness-based. He initially wants his share of the money because it will allow him to split from Per Haskell and start his revenge scheme over Pekka. He then pursues getting it with such zeal because Van Eck broke their deal and Kaz (rightly) feels cheated; Van Eck contracted him for a job, which he successfully completed, and then refused to pay him for it.
He fixates on destroying Van Eck because like Pekka Rollins, he broke his deal with Kaz and scammed him out of his money. It's the scamming and deal-breaking (and his inability to figure it out beforehand) that hit Kaz's pride and motivate him. If it were really just about the money, he could have gotten it any number of ways. But despite talking a big game about worshipping money and it being his primary motivating factor, he throws away an awful lot of opportunities to get and keep it during the duology:
He doesn't take the Ice Court job until he's shown the effects of parem and promised 30 million kruge (enough that when split he could realize his dreams of splitting from Haskell and taking out Rollins)
He gives up his shares in the Crow Club and Fifth Harbor to Pekka in order to rescue Inej and kickstart the Sugar Silo scheme
He doesn't abandon Inej after she's taken by Van Eck to sell Kuwei to the highest bidder, even though that would have been the most logical and lucrative option (as both Inej and Matthias think about)
He liquidates all of his existing financial assets to free Inej AND tells her where his emergency stash is so she and the rest of the Crows can get out of the city safely
He gives Rotty and Specht Per Haskell's share of the Ice Court Heist money (recognizing their loyalty and help) and Nina Matthias's share (to somewhat compensate her for her grief and fund her new cause) instead of keeping it for himself
He buys Inej a ship with HIS part of the money
And while several of the things he abandons money for are for Inej, to keep her safe and free and happy, the rest of the Crows and the Dregs at large benefit too. So do people he's probably never met. Pre-canon!Kaz fixed up the Slat with his own money so it's a safe-ish place for the Dregs to live, for example, and in Crooked Kingdom he totally goes along with Nina's plan to get all of Ketterdam's Grisha onto the boat to Ravka after a mostly token protest even though it massively complicates his plans.
It's pretty clear that no matter what he says, at the end of the day Kaz values loyalty, fairness, and keeping his promises more than he values money. The money is just a means to an end for him: he wants it because it will a) allow him to have an amount of safety and security for himself and the people he cares about (and those who have pledged their loyalty to him), b) let him keep his deals with and promises to said people, and c) give him the ability to one-up Pekka and destroy his empire.