The author assumes that "the media" are some homogenous lump that all thinks the same and pumps out the same content.
Each media company has a target audience, and it optimises for that audience continuously. Their viewers or readers like that "property" because it's views/biases/style reflects their own.
> "The media is becoming more progressive"
that's a broad sweep. The demographic is changing and the various properties are changing to reflect that. Granted, there is some leeway in a media organisation pushing it's audience to one side of a debate or other. However it needs the audience to go with it. However there is no evidence provided that this is the case.
I think the bigger issues is that people have realised that a small number of business are increasingly becoming arbiters of _everything_. Be that Tv shows, what opinions are penalised, who can trade where and for what price. (See the backlash from Facebook's fucking stupid PR spat against apple.)
In short, I don't think the author was able to fully express their claim without making broad unsupported statements. Finally I don't think a16z's media push is going to get overly far _unless_ they provide content that people want to consume at the correct price and place.
If you want to see what I mean, just look at what happened to the "let's disrupt hollywood" Effort, which amounted to nothing. (hollywood is disrupted, but by the pandemic, disney, amazon and netflix, not a startup)