There is now a 10% GST or tax on imports of overseas services, so that and the falling AUD provide some explanation. The reality is of course that yes, they are increasing prices because they can, you are sort of locked between a rock and a hard place. I don't even use Lightroom, but my Photoshop CS5 no longer works with Sierra, so I am sort of caught.
The ACCC is supposed to act on collusion on pricing between say BP and Shell on the price of petrol or Woolworths and Coles on the price of food. However they have completely failed on this. They are also supposed to prevent a company with a monopoly preventing competitors. They blocked Telstra from putting in a free nation wide optical fibre to the home network in 1996. So 20 years later we have a crap Internet service over copper. In short, the ACCC has been a complete waste of public money and generally detrimental to the country.
Here one company is providing its own product. If it was cure for cancer then there would be a case, but if it is just an image editing programme then you have a choice to use another. I doubt that there is much they can or would do.
It is a great example of how a company would rope people into a "honeymoon" deal and then increase prices. Banks do this all the time.