I think it exhibits a brighter perspective on life rather than emphasizing the reality of the era. This clip exhibits opportunity and hope. I agree with Popcorn97, we go to movies in our good and bad times and we expect to see movies that make us feel better about ourselves, though that isn't always the case.
Definitely greed and desired omnipotence are recurring themes particularly in Depression era musicals. When times are low, people will do whatever it takes despite the morality or legality to get what they want, and their actions easily supply the conflict of some great shows.