YouTube could be worth $400 billion — that's more than Disney and Comcast combined. We should be paying more attention.

• Google bought YouTube for $1.65 billion in 2006.
• Now YouTube could be worth as much as $400 billion, per analyst Michael Nathanson.
• YouTube is really big! Yet somehow, it flies under the radar for most people. That's weird.

YouTube is the world's largest video platform. It's the world's second-largest search engine. It plays a massive role in culture.

And most of you don't pay nearly enough attention to it. But Wall Street does: Analyst Michael Nathanson has a new note out estimating that YouTube could be worth as much as $400 billion as a stand-alone company.

Reminder: Google bought YouTube for $1.65 billion nearly 20 years ago.

We could spend time here explaining Nathanson's math and assumptions — he thinks that in 2023, YouTube generated operating profits of $5.5 billion on revenues of $45 billion; he also thinks its future growth will be spurred by subscription services like YouTube TV, as its advertising growth slows.

But let's be honest. Those numbers aren't going to sink for many of you. Just like YouTube's massive size doesn't seem to register with politicians like the ones on the US Senate Judiciary Committee, who hosted a big hearing on "Big Tech and the Online Child Sexual Exploitation Crisis" in January and grilled the CEOs of Meta, Snap, TikTok, and platforms — and gave YouTube a pass.

So let's try this argument: You know how people like me spend a lot of time tracking who's "winning" the streaming wars?

Line up YouTube next to all the big players, and you'll realize, like my colleague Lucia Moses pointed out last month, that it's ridiculous to have a streaming wars conversation without talking about YouTube.

For instance: If you took Netflix ($261 billion market cap) and added in Paramount ($8 billion), Warner Bros Discovery ($21 billion), and Fox ($14 billion), you'd have a company with a combined value of … about $300 billion. Throw in a Roku ($10 billion) if you want. You're still not getting close to the $375 billion to $400 billion value Nathanson is talking about.

Or, alternately: You could combine Comcast ($172 billion) and Disney ($224 billion, after a big ramp-up this year — Nelson Peltz, your services are no longer needed) and end up with a $396 billion company. (You would also get to watch a funny wrestling match between Disney CEO Bob Iger and Comcast CEO Brian Roberts who have a long-standing enmity.)

But those two companies aren't solely reliant on media to make their money — Disney is also selling cruises and theme park passes; Comcast is one of the biggest broadband providers in the US.

So if you're talking about video, and the internet, and advertising and audience and value and you're not talking about YouTube? You're doing it wrong.