There's plenty of 19th century fiction that goes into it --- that explores, like Dombey and Son, how trade, or via a character like Rouncewell in Bleak House, how industry, generates wealth (or later in the century: Hardy shows how agricultual economies work, in general as well as in specific human terms). This isn't really a feature of 18th-century fiction though, and you're right to identify Austen as at the boundary-line between 18th-century novelistic forms (Richardson, Fanny Burney etc) and 19th-century (the Blindungsroman, irony etc).

That said, it interests me that there was a distinct sub-set of 19th-century novels that critiqued financial speculation (investment, the stock exchange etc) as a ground of wealth: Dickens's Merdle (in Little Dorrit, 1855-57), Charles Lever's Davenport Dunn (in Davenport Dunn, A Man of Our Day, 1859) and Trollope's Melmotte (in The Way We Live Now, 1875) are all iterations of the same basic story—plausible confidence trickster from a dubious social and/or racial background creates a bubble in the world of finance to get rich, buy himself a title, hobnob with aristos (all of whom fall over themselves to be associated with what they assume is the endless fountain of wealth the financier represents). Inevitably the bubble bursts and the speculator dies (H G Wells's Tono-Bungay, 1909, is a late example of the same thing). The remarkable thing is that I don't know of any counter-representations to this narrative—I mean, Victorian novels in which investment in shares, or financial speculation, is shown as paying off. Yet investment is one of the key motors of wealth under the Capitalist system.