I doubt most cannot be articulated, but I think it quite likely there is valuable knowledge that is expensive to articulate, sometimes to the point of complete

I doubt most cannot be articulated, but I think it quite likely there is valuable knowledge that is expensive to articulate, sometimes to the point of complete impracticality, and in that sense "can't". Instances of actual inability to articulate, due to Godel incompleteness or similar, seem rare. Technology applied to knowledge can change the expense.