Have they? Or perhaps trash media is the bottom of their list of priorities? Maybe they are overloaded with cases and need more support? There are many more possible explanations than "shown they are unwilling"
You can take a look at some recent current and pending antitrust cases on the DOJ's website:
https://www.justice.gov/atr/antitrust-case-filings?search_ap...
In fact there was just recently action taken against Disney, which forced it to sell of major parts of 21st century before it was allowed to proceed with the merger.
https://www.justice.gov/atr/antitrust-case-filings?search_ap...