[SiVal]

Money has a lot to do with it. When a company is booming, people tend to be optimistic, generous, enthusiastic, and feel secure. The company is more generous and "enlightened", and their success feels like your success.

When a company is struggling, people get insecure, start worrying more about who gets credit to avoid layoffs, a gloomy mood spreads to everyone, the company starts taking away goodies and people get resentful, and so on.

You could repeat the question with, "assuming two companies are in the same X financial state and changing at a rate of Y, what causes one to have a better culture than the other?", because there is clearly more too it than money.

Even so, the rest of the factors float on top of the money tide, and it makes a world of difference whether the tide is coming in or going out.