This has also been my concern with Dave Ramsey. While I like his emphasis on becoming and living debt-free, and believe he knows 1,000% more than I do about handling money (he has had more to handle, so he has had to learn things I would have no use for), I do not think that pursuing the American Dream has a biblical basis. I have always been content with what I had. I lived in genuine poverty for decades—a condition to which I never objected, and in which I never lacked. When I married Dayna, she already had a house (a nicer house than I had ever lived in before), so I am pretty comfortable, for the time being. I took over the mortgage payments when we got married, and, if anything would happen to her, she knows what would happen to the house.
Today, I have more than at any earlier time in my life, but it has allowed me to increase my standard of giving, as well as my standard of living. In fact, my present percentage of giving (which has continually increased regularly over the years), currently leaves me, most months, with nothing left over after paying for housing, food and utilities. I never plan to retire, and have laid nothing up for such a contingency. I don't think Dave Ramsey would feel too good about my situation. Since I was 17 (I am now almost 63), I have trusted the Lord for my provisions, and have never been disappointed.
While I don't think everyone is called to live as I do, I also don't think Christians are encouraged in scripture to seek comfort or affluence. God gives some Christians affluence, but it seems to me that this is primarily because they have been gifted for a ministry of giving. Here is where you find the biblical principles on money: Matthew 6:19-34 and 1 Timothy 6:6-11,17-19. I don't find many modern Christians consulting these passages in their financial decision-making, but the principles will still be valid so long as there are poor people, so long as there is a God, and so long as He has a kingdom to be promoted.