The analysis of Henry Ford's Model T creation scene is ambiguous, but the case can be made that Doctrow is criticizing modernism and a single-minded pursuit of progress as dehumanizing of the workers. While there is a certain air of reverence, Ford is portrayed as slightly cold, and the reader is left with a feeling of unease at the joy taken from reducing human beings to parts of a machine.
Naturally, critique of Fordism has ramifications for Tateh, who in the previous chapter, strikes it big with the novelty store, agreeing to sell his flipbooks. In class, we discussed Tateh having "sold out"; his artwork being corrupted by his new contract for the "mass production" of a total of four flipbooks, all of which will still be handmade. After all, the happiness of his daughter is much purer a purpose for art than the acquisition of money.
Even though his newly earned money would be used to provide for his daughter. Even though, I image, the Little Girl would rather eat than hold a monopoly on her father's flipbooks. In fact, the argument that, somehow, Tateh is corrupting his artwork by making money off of it is slightly reminiscent of the superficial glorification of destitution that we see in the poverty balls of New York's high society. Which, by the way, Doctrow clearly hated, judging by the scathing irony that he treated them with. I don't blame Tateh for "selling out" on this very minute scale. It doesn't corrupt his art, and the assumption that it's purer when he was poor -- the beauty of the starving artist -- is kind of patronizing.
Now, another layer of his joining the ranks of American entrepreneurship is that he abandons his radical political associations: "Tateh began to conceive of his life as separate from the fate of the working class" (131). If any part of his actions have been "selling out," it would be this. However, if we assume that Tateh's driving life's purpose has been to care for his daughter -- and we have no evidence that would challenge that assumption --, then he really wasn't selling out from what really mattered to him at all.
A not directly related point, but an interesting one: it seems that along with Tateh, Doctrow has abandoned the radical leftist political philosophy that is slightly implicit in his portrayals of the slums. As Iulianna noted in her most recent blog post, Doctrow treats Tateh and his situation with a lot more sincerity than he treats the situation in New Rochelle, suggesting a sort of alignment with the slums.