The notable exception is Scrooge, who, as we all know, changes dramatically by the end. No coincidence, I wager, that A Christmas Carol is Dickens' best-known and best-loved work. (Plus, the 3-ghosts trick is a pretty cool plot device.) Others in the story are exactly the same from start to finish, though that's okay for supporting characters.
But elsewhere...egh. I sat through a dozen performances of Oliver!, in the light booth a few years ago for community theater, so I can safely say I know that story in and out. Oliver Twist, as the protagonist, doesn't really change. His circumstances change, but at the beginning he's a good-hearted, suffering, brave orphan boy, and the end he's still a good-hearted brave orphan boy, but with less suffering since now he has an adopted family. He basically wanders around the story getting batted from one set of adult caretakers to another, without changing as a person. Fagin doesn't change, of course, either. Neither does Dodger. They're interesting as portraits, but they don't quite seem three-dimensional. Nancy almost changes, but dies before she gets too far.
OK, but Oliver is young, and the story only covers a small portion of his childhood. Maybe something bigger? Well, same problem in Great Expectations, which I slogged my way through a couple years back after Amazon kept insisting to me that I'd love it. Pip starts out as a good-hearted, suffering, brave orphan boy (hmm, deja vu), gets his hopes raised, gets his hopes dashed, gets his hopes raised again, gets his hopes dashed again, and ends up a good-hearted, suffering, brave adult. Throughout, he is likeable but frustrating: he keeps waiting for life to change for him; for his "great expectations" to finally kick in and for things to magically improve on their own. Nothing he does makes any difference, and he ends up older, a little wiser, and ultimately not different enough to keep me from closing the book in disgust and vowing to stop reading Dickens.
Now, Miss Havisham, in the same book, makes a very memorable figure out of her habit of not changing. She takes it to such extremes that it's actually interesting. But you can't have all the characters fail to change, and just stand there helplessly while circumstances morph around them. At least, I wouldn't think you could, but Dickens' huge popularity seems to suggest I'm wrong. Maybe if I read Bleak House or something I'd change my mind on this whole thing. You tell me.
Aw, but Molly (you may be saying), back in the early 1800s in England, people's financial circumstances really were out of their control for the most part, and really did dictate their quality of life. You came into money, or you didn't, and your whole lifestyle hung upon the point.
Okay, true. I know that. But one can read other books from that era (or set in that era) and get the same dilemma, while meeting characters who actually do change from start to finish. Take Pride and Prejudice: the Darcy/Elizabeth love story is such a delight because it involves such internal struggle and revision of prejudices for both of them. They go from "You? Why would I want to dance with you?" to "Okay, I've thought it over, and despite your awful family and all the other social difficulties, I've decided I can't live without you; and you know what? Screw the rest of the world." Same case in Jane Eyre, with even bigger social difficulties. Les Miserables is chock-full of characters who undergo tremendous shifts in their world-view. It leads some of them to suicide, some to repentance, some to tragically noble ends, and a select few to redemption, but man, you stand still in Les Mis and wait for your expectations to improve, and you're either going to starve to death or get a cannonball in your chest.
I apologize to stalwart Dickens fans. This is, of course, just one reader's opinion. But I've long tried to place why I groan when I imagine tackling another Dickens novel, but fervently wish someone would uncover a lost Bronte novel; and I think I've come close to the explanation here.
All the same, tip of the hat to Dickens, who managed to write a zillion novels while supporting some dozen children, and who brought the country's attention to the atrocities of child labor and poverty, and is still a household name almost two centuries later. May we all fare half as well in our final curriculum vitae.