Them existing and Google being able to enforce people turn them on, and consistently blocking everyone who doesn’t, is a whole other problem that is a lot more complex.
It’s not practically feasible because people will find ways around it. The app can require an eye tracking features to be turned on, but people will go to the browser site. If they get the people making a browser to integrate it, then people will use another browser. They’d have to block access on any mobile browser that doesn’t enforce it, and that’s a futile effort.
At least on IOS, they tried to lock Picture in Picture and background play behind a paywall, but that only worked in the app, and both features still work for the mobile site with a bit of fussing. Just because they implement restrictions and features doesn’t mean they can actually get them to work enough that people won’t glitch around them.
Default is 60s ad block. However, enabling 'Regular User' feature will bring this down to a more convenient 15s block so you get your content faster every time. To enable this feature, tap Allow when prompted for camera permissions.
I remember playing with a similar feature on my Galaxy S3 back in the day. Eye scrolling. The phone would scroll for you when it sensed you looking at the bottom of the screen. That was the S3. It was not perfect but very usable. My hands always felt faster so I never kept it on but it was a fun thing to play with. I'm sure the only thing stopping them is the fear of backlash. We'll get there in time I'm sure :/