The move from RNA to DNA and the necessity of reverse transcriptase
Yes, this is true. This flow of information is called the "Central dogma of Molecular Biology". It basically describes the flow of information from DNA to RNA to proteins. Since a virus needs to amplify its genetic information before it can take over the infected cell and make only viral proteins and its genetic information, it has two possible options.

DNA viruses can use the cells replication and transcription machinery to make copies and express proteins. RNA viruses either have to use a reverse transcriptase to make DNA from its RNA genome to go on like the DNA viruses. Or they have to have a special, RNA-dependent (works only on RNA templates) RNA-polymerase (our RNA polymerase are all DNA-dependent and work only on DNA templates) to make more copies of their genome. Our DNA polymerases are dependent on DNA, the same is true for our RNA polymerases. So if the virus is not encoding (and actually bringing a few molecules with it in the virus) of the RT-polymerase or the special RNA-dependent RNA polymerase it will not be able to spread.

Using ribonucleotide reductases would theoretically be possible, but it is not the way nature went. And since a cell contains huge amounts of RNA, I doubt this would be a feasible way, as the enzyme would reduce all RNA. And later on the new viruses also needs new (not reduced RNA) to be packaged into new viruses. This would also be problematic.