Most of the world’s population has been more confined to the same four walls than usual in recent times, but it’s almost like Brian Roberts has spent months living in a cave. The Comcast CEO has evidently not been keeping tabs on how telecommunications and media just don’t mix in the way that many expected, despite multi-billion dollar attempts to tie the two incompatible businesses together. While Faultline was taking a summer break last week, reports surfaced about Comcast plotting moves for either ViacomCBS or Roku. Acquiring ViacomCBS would be a mistake, given the volatile behavior of current parent company National Amusements and controversial owner Shari Redstone. This is perhaps why a “tie-up” with ViacomCBS has instead been floated by…