First of all, there was no "light" seen in the transition from ThickNet (RG8) to UTP. It was purely economics. Back in the 1970's and 1980's, as personal computers started to appear in businesses, the standard network media was coaxial or twin-axial cable. However, no office buildings had much, if any, coax or twinax in place. They did have a LOT of twisted pair. So, a product called LatticeNet appeared - the first commercial implementation of the ethernet protocol on twisted pair. Shortly thereafter IBM came out with their Token Ring network that ran on Cat3 wiring. For a lot of early implementations, unused voice pairs were used. As speeds pushed higher, the wiring specs became more stringent and new wire was pulled anyway, but by that point PCs were now where most computing was being done. Secondly, what power adapters are needed for MOCA? MOCA was not designed to a general purpose network solution. It was conceived as a way to get IP traffic to the same place you were already running coax for TV purposes. I know of no network knowledgable person that would advocate using MOCA where there is no need for TV distribution over coax. Finally, I have rarely seen properly designed and implemented Cat5/ethernet networks in people's homes, so there are PLENTY of was to mess up Cat5. The most common error I see daisy chaining switches, which will have direct impact on performance. WiFi installations are even worse. The mixing of MOCA and Cat5 is usually the least of the problems.