People aren't compelled to try a financial service to spend more wisely. They're compelled to try it because it "earns" them more (more interest, cash back, etc). Might be the same thing, fundamentally, but psychologically, it's not. Greed is good.
Some people are driven to change banks because of interest rates, but those people are not the majority. Most people change banks around major life events: moving, getting married, getting your first job, etc. Or, they change banks when they have an extremely negative experience with their current bank.
Either way, changing banks is a hassle, and we really have to make it easy and compelling. But interest/rewards aren't the only motivation, or even the primary motivation, for switching one's bank according to bank industry research.
