Ownership:
NYT - billionaire Sulzberger family
WaPo - Jeff Bezos
LA Times - billionaire Patrick Soon-Shiong
Disney/Comcast/Paramount represent the consolidation of an industry that used to be hundreds of independent newsrooms into a dozen or so corporations. The murdoch family's New Corp is regularly analyzed as a political force on par with individual elected leaders, if not more so.
Entertainment: Apple/Amazon/Comcast/Disney/Sony/WarnerBrosDiscovery/Paramount
The problem is that the industry has consolidated into a number of players you can count on one hand.
On the national level, there are multiple sources of news (NYT/News Corp/Disney/Comcast/Paramount/WaPo/LATimes/etc). There are lots of sources of professionally and amateur produced entertainment. Apple/Amazon/Comcast/Disney/Sony/WarnerBrosDiscovery/Paramount/etc.
If anything, the monopoly exists on wired broadband to peoples homes, which is usually only available from one seller.