Here's my theory, and anyone please feel free to strike it down.
I think it's become clear that Austin can and will shine in a No. 2-type role. I say a No. 2 role because, even though he's clearly been our go-to guy in recent weeks, teams haven't paid him the attention given to true No. 1s. As you said, we still don't know what will happen when that occurs.
But say teams start to devote a second man to Austin and he happens to flounder. As long as he still dictates that second man -- perhaps even in a role like the one T.O. had last season where his reputation, not the production, generated fear in opponents (see: the string of sub-60 yard games T.O. had) -- it'll still do sooo much to free up other players, particularly Witten. Without T.O., Witten's deep play ability seems to have been taken away. He's been an underneath, safety-valve type guy this year. If Austin suddenly requires a second man, Witten is unleashed.
The alternative for the defense then becomes to take away the safety from Austin, but he's clearly shown he can and will excel with just a corner on him.
Of course, the elephant in the room remains: Will Roy ever shine as everyone else around him takes away all the coverage? One reason we traded for him was to have a legitimate second threat opposite T.O., who was taking the coverage but not producing like in the past. Maybe Austin becomes that guy this year -- a player who is doubled but can't produce the numbers he is now. That's when we could really, really use Roy to make a cameo on Sundays.
