Lets put paranoia aside for a moment, how would this even be feasible? Firstly the browser has to ask permission to use the camera

Hey maybe you're the one in a million that uploads videos direct through webcam so they have that permission anyway - Would people really be ok with sitting there as their webcam light flickers on and off to make sure they're watching adverts? No, they would not. Literally any rival tube site could milk the heck out of that to start pulling people away from YouTube. I'd put money on seeing people vlogging on an adult tube site before we see eyeball tracking on YouTube.

Besides all that you could just unplug your webcam..

Oh, you say that now...

460p unless you meet the hardware and software requirements.

Eye tracking hardware and HDCP 4.0 display, and Windows 10 Securibility Update or MacOS Himalaya.

iOS 10 or Android Sherbet.

On MacOS and iOS that's Safari with iEye permissions granted for YouTube.com, or Chrome on MacOS with GoggleEye enabled.

On Windows, it's Edge with Windows Accessibility and Optics (WAaO), or Chrome with GoggleEye.

Android is Chrome with GoggleEye.

Or the official iOS, Android or Win 10 apps.

Coming 2019. Maybe.

Trips up at the first hurdle - 460p unless you meet the hardware and software requirements

That's a sinking ship. That's the sort of thing that allows Facebook into the world despite MySpace already existing. The sort of thing that allows Google to elbow its way into the #1 spot past the Altavistas, Hotbots and the Jeeves. A new site would come out of nowhere that doesn't have that restriction.

460p is a low bar but these restrictions already exist on current services.

Netflix: https://help.netflix.com/en/node/23742 - 720p on Chrome and Firefox, 1080p on IE and Safari and 4K requires Microsoft Edge, a HDCP2.2 display, a 7th generation Intel Core CPU and Windows updates.

Amazon: https://www.amazon.com/gp/help/customer/display.html?nodeId=... - You can do 1080p on pretty much any browser but 4K requires a 2nd generation Amazon Fire TV and a HDCP2.2 display.

There is a big difference between restricting to standard definition and high definition though. Many people now have devices that will show the difference between low and high definition, not as many have 4K capabilities.

In the future these values will go up of course, but the difference between restricting HD users to SD and 4K users to HD is quite different.

I wasn't being entirely serious, and apologies if I didn't make that clear.

That said, YouTube have foisted some odious crap (cough random unsubscibe cough Google+ cough Takedown bullshit cough) on creators and subscribers, and yet here we are. Still using YouTube.

The cost of starting and acquiring users for and running a viable YouTube alternative is just too damn high. Unless Amazon do it, it's not happening. Vimeo is an also-ran despite.

People would just upgrade their shit and/or fall in line, or suffer shitty quality.