Won't work with biometric attestation. For example, banks in China require periodic facial recognition to continue the banking session.

What's stopping these companies from offloading the scraping onto their users?

"Either pay us $50/month or install our extension, and when prompted, solve any captchas or authenticate with your ID (as applicable) on the given website so we can train on the content.

yea but those are not open sites, try imposing that on an open site you'd want to actually attract human traffic to

see, literally, reddit requiring teenagers to open their mouth and roll their heads around to enter.

I heard that it could be easily bypass through realistic 3D human game model with basic mouth open and head tilt animation, even gmod can do such thing.