Whether or not Google or Facebook directly profit from the use of news content isn't, and arguably shouldn't, be a consideration as to if they should be required to pay or not. This is copyright logic we're working with here: the harm isn't that Google or Facebook found gold in someone else's sandbox, it's that they were digging there at all. We create the law specifically to make money move from one pocket to another, not to satisfy an underlying concept of justice.
The thing is, if this was just a new related right, like the EU Copyright Directive, we'd see the market play out as usual. News corporations would realize that Google and Facebook actually are paying them in valuable exposure, and sign away their aggregation rights for free or little cost to the aggregators. Australia appears to be trying to do an end run around that by taking away as many negotiating options from Google as possible. Effectively, there's one massive news collection society and anyone who carries news at all, regardless of who it's from, has to play ball with them. They also are legally required to get what is effectively most-favored-nation status. This is such an oddball way of doing things that I see this either crashing and burning so hard that the courts have to bail out Australian Parliament, or it works perfectly, becomes the new model regime for funding news, and winds up in the next set of WTO treaties (whenever those come around).