Is it that they prefer media from juggernauts or that they're more likely to know of media from juggernauts?

Juggernauts are able to put their movies in theaters or cable/streaming television, put trailers in front of other movies or tv shows, take out billboards, etc. Juggernauts are able to market the hell out of their products, while most little guys don't have that opportunity.

I imagine that this also has a lasting effect. For example, juggernauts are more likely to have a streaming service trying to pick up their media while also putting that media ahead of little guy's media in that streaming service's recommendations. I'd also guess that over time the probability of organically finding little guy's media drops at a significantly faster rate than juggernaut's media .

Well, we have studios like Blumhouse that create low budget movies that do get a lot of press, have trailers, get plenty of promotion etc. They do well on an ROI basis. But they don’t top the box office.

Since 2014, all of Blumhouse's movies are owned, distributed, and co-produced by Universal Studios. Well, except for their BH Tilt division, which is partnered with Neon for co-production and distribution. Their most notable low-budget film that kickstarted their rise was Paranormal Activity, which was straight up acquired by Paramount Pictures for an actual theatrical release.

Blumhouse wouldn't be where they are without the juggernaut's purposefully propping them up.

People spend their attention here, not their money. YouTube alone has far more watch-time than cinemas or Netflixes.

But how many people are willing to pay $15 to watch 2 hours of YouTube videos?

How many paying subscribers does YouTube have compared to Netflix?

It's because there is no reason to pay for something you can get for free. The YouTube premium value proposition is different.