There can easily still be no wiretapping equipment upstream of the servers; the companies are already copying the data directly to the collection equipment anyways, so that can be a parallel path. I'm not sure a place like Google or Facebook would ever choose to participate in something like this if their whole business were one misconfigured serial-path wiretap server away from being completely down.

I believe the NYT had mentioned a couple of days after the story broke that 'real-time' collection was possible. Even that is easy technically, you just send a copy of that instant message or video frame to the FBI collection server as it goes out.