In order to coax George Bailey out of committing suicide, Clarence the angel shows George a vision of the future where he'd never been born: His brother is dead, his friends are drunks, and his beloved town of Bedford Falls has transformed into Biff Tannen's alternate Hill Valley 1985. Reinvigorated with the knowledge that his life is meaningful, George returns home and happily spends the season with his family and friends ... all of whom are still doomed by his existence.
And not just because they gave up their life savings to make up for George
neglecting to put his uncle in a home.
You see, during the movie, we see George bring a manufacturing industry to Bedford Falls through (among other things) his new housing project, Bailey Park. That might be great for Bedford Falls in the short term, but the manufacturing industry isn't exactly doing so great nowadays, particularly in the upper states like Connecticut and New York, where the film is set. If you can't picture what happens when a major employer such as the manufacturing industry goes sideways, take a look at Detroit. The effect would have been felt even worse in a small town such as Bedford Falls. Look at what almost happens when George's doddering uncle loses the deposit -- the entire town loses its mind and everyone makes a run on the bank. Now picture those exact same people all getting laid off from their jobs at the same time. Bedford Falls would turn into fear-gassed Gotham city from the end of Batman Begins.
Angels get wings, and bankers get stitches.