I disagree with Dave Ramsey on a few points, but in general, I like what he's doing, and, let's be honest, he's pretty popular. The more people listening to a talk show that talks about getting out of debt and staying out of debt, the better.
Yes, once you've got your financial house in order, his advice is a bit less useful, but that's not his target market. His target market are people whose hair is on fire, has been on fire for a few decades, and will be on fire until they die if they don't change something. And, to that audience, his advice is radical and life changing.
The details of where to invest your money only matter if you have money to actually invest.