Both Cohen and Manafort were privy to conversations with Trump in addition to those that Cohen taped.
Mueller at this moment is a black box, and he hasn't opened the curtains yet. You can infer everything that is possible, given everything known from outside the box.
I'm trying to imagine what went on in the Manafort jury-room. Would it have been the case that there were so many charges that holdouts worried about the case's implications for their Great Fuhrer could only thwart the 10 of 18 charges? And they can re-try those mistrialed charges. In addition, I think Manafort is facing another trial in the DC jurisdiction.
Trump's personality disorder -- his psychological disorder -- makes it a continuing and longstanding good bet that he can't keep his mouth shut about anything. That's why his collusion is evident from the "hack Hillary's e-mails" event, with the timing of more Russian intervention on that very day.
Perhaps nobody has thought much about a possibility that they can get someone in Russia to testify in the US with documentable knowledge of the Kremlin psy-war play-book, or even to fill in the details linking Trump in more damning ways.
What is Trump going to do? What is the New York state's attorney going to do? What more will Cohen say? What more can Manafort offer? And of all the Americans indicted so far, what do they know about each other? And Trump, of course?