These systems are designed to teach you discipline. Unfortunately they are cookie cutter and they do not fit everyone exactly. Its much like dieting, if you dont continue the diet after reaching your goal, you will end up back where you were before. Once the discipline is established, you can start tailoring your own method. For example, if you do indeed have cars at 1% interest rate, you're much better off putting the difference in a CD. It really comes down to what a person prefers. Personally I find the DR method designed for people with low income.
Yes, I feel the same way pertaining to the low income as I listen to his shows on the radio. I was fortunate to refinance my house in 2012 to a 2.8% and lock one car for 1.7% and the other at 0.9%. As far as the total interest on cars over 5 years, I have already made that back in the market in the first year. However, just need to find ways to get it through to my wife's head since expenses have gone up with the new baby. I have a financial goal I want to be at in 3 years. I will not stop until I get there.
It is really not about being able to make a few more dollars in the market over the interest you are paying...that's likely peanuts in the grand scheme of things, it about the elimination of risk and debt with his system. I'm not low income and I follow his system, it works equally as well for all. I agree there is other ways for people to do finances but his methods are proven and they will work for anyone who wants to get out of debt and build real wealth.