Why do scientists hypothesize that rna was the first form of genetic material?

RNA is an intermediate macromolecule fabricated using genetic code resident in DNA and there are multiple types of RNA. The immense complexity of DNA mixed with the catch-22 of protein coding and construction convinced naturalistic biologists that a DNA/protein complex system is too complex to have arisen naturally as first organism for the origin of life. The function of RNA is varied but does include protein synthesis, proteins being the key structure within all organisms. Lab experiments demonstrated that some types of RNA could be assembled under the right conditions, however, the key function of an RNA assembly to replicate itself has not been possible, and the conditions under which RNA assemblies have been produced are not geochemically relevant to  primordial Earth conditions. Additionally, There are no natural forces or processes capable of the complex organization, even in the simplest form of RNA cited. This lack includes mitigation of RNA mutations, rapid degeneration, affinity for contamination, and the probable impossibilities of “chance.” 

The simpler level of complexity and the potential for replication have made RNA attractive, but it absolutely fails to solve the issue of origin of life functionality.