The RNA Intermediate

I came across this great paragraph in Principles of Population Genetics by Hartl (3rd ed):

The central role of RNA in gene expression is one of the oddities of biology taht makes sense in the light of evolution. That gene expression is configured around RNA is a legacy of the earliest forms of life when RNA molecules served both as carriers of genetic information and as catalytic molecules. The role of RNA as carriers of genetic information was gradually replaced by DNA, and the role of RNA as catalytic molecules was gradually replaced by proteins. At every step along the way, as the RNA world evolved into the DNA world, the role of RNA was indispensable in the processes of information transfer and protein synthesis, and so the RNA intermediates became locked in place.

An apt summation of the idea. An interesting aspect is that indeed RNA still does retain it's catalytic capabilities (i.e. regulatory) in many organisms and also it serves as information storage in many viruses, and there is even some evidence of that role in plants. So despite the ancestry of this division of labour, RNA still seems to maintain it's "ancestral" roles, and is not simply an intermediate between DNA and protein. I wonder what the future holds in terms of DNA as catalytic and protein as information storage. Perhaps some findings will change the dogmatic views of the roles of these molecules also.