>Can you really earn that kind of valuation peddling new credit cards and refinanced loans?

I think so. That's a huge market.

Honestly, I think it is a win-win. I don't have any loans but if I were to have a big loan like a mortgage I would welcome offers from leaders who could save me a significant amount of money. Many people I know have refinanced their mortgages at some point in the life of the loan.