Imagine cash is like a party-goer who's not having fun at one party (the banking system), so it hops in a cab and heads to another party (alternative investments) to find better tunes (higher yields).
Now, those bankers, they're like DJs trying to keep the party-goers dancing and happy with fresh beats (new, creative financial products) as long as the cover charge (fees) is a good earner! But sometimes the party police (regulators) don't dig these "fresh beats.
Oh, and BTW, Bitcoin is the best rave party!