Storage isn’t cheap

Network bandwidth isn’t cheap

Data centers aren’t cheap

Add on Electricity, Transcoding, Multiple AZs, Backups, cached content with ISPs and engineer salaries and you’ve got a very expensive system.

That’s not even factoring in payments to creators, which are necessary if you want people to make quality content for the platform.

Your website serves multiple orders of magnitude less traffic than a single YouTube page. Web costs aren’t linear. It’s an S-Curve where it’s incredibly cheap to get started, but gets exponentially more expensive until you’ve reached some level of critical mass where revenue exceeds costs.

Video hosting pre-YouTube was terrible. It barely existed, and it wasn’t accessible. They sure didn’t invent it, but they made it possible for the masses to host video.

No other web content platform has taken off since YouTube. There’s a reason for that, and the majority is cost. To reach a widespread audience you have to invest hundreds of millions into infrastructure. Same reason Twitch still has the critical mass of livestreamers.