So the story is set contemporaneously, so we're talking the 1840s. Scrooge is depicted as an elderly man, which in those days would put him in the 50+ bracket. Let's say he was sixty at the time of the story. born in the 1780s. So the Napoleonic Wars would have begun around the time he reached 21 and could go into business for himself. Much of Britains' finance and industrial output at that time was geared toward the war and the protection and maintenance of overseas colonies. Making loans to and buying shares in companies who had Government contracts would be a profitable business.Scrooge and Marley would have been coining it. When the wars ended in 1815, the British economy was so focused on wartime conditions, and dependent on military contracts, that peace almost wrecked it. It is at that point, I suspect, that Ebenezer and Jacob changed their ways. Many of the shares they owned would have goen down in value, and they would have had to sell them fast. There would also have been defaults on loans. At that point, they might have decided to become more ruthless - taking assets in place of payment and selling them on, for instance. They were probably forced into a miserly lifestyle just to break even, and caution kept them that way when things improved because now they knew that it could all change at a moments' notice. There were no pensions then, and if a time came when they were unable to work, they would need those savings to live on. Marley died in harness, but Scrooge would still be concerned about his old age.
As to 'poor Bob', his 15s a week was actually 4s above the going rate for a clerk at a small company. Scrooge also gave him Christmas Day off, albeit with some grumbling (it's implied that Scrooge himself would be in the office that day). Be it noted also that, despite having to pay for his daughters' apprenticeship, Bob could afford to rent an entire house just for his own family (very rare until at least the 1930s). The Cratchits did not have to sublet to a lodger, either. They could afford a goose (back in those days, pork or rabbit was more usual) a quartern of brandy for the pudding, gin and citrus fruit (by no means cheap then). Doctors' bills for Tiny Tim would, however, have been out of the question, even for people on a much higher income.
This implies to me that Dickens had less of an idea of the levels of absolute poverty that existed in those days than is generally thought.
Not that it affects the main story, which is that anyone can change, and that there is no point in wealth if it's not used to produce happiness.
