Network bandwidth cost is negligible, it's hardware and processing power that's expensive. Each query I process is up to a 100 Mb disk read. I only have so much I/O bandwidth.

As far as I see it, there are two bad solutions to this problem.

The first bad solution is to have a central authority inspect most of the web's traffic and try to deduce who is human. This is the approach taken by Cloudflare, but essentially the same as Remote Attestation. It gives the chosen authority a private inspection hatch for most of the web's traffic, as well as unfettered authority to censor and deny service as they see fit.

The other bad option is a sort of 'free as in free enterprise' Ferengi Internet where each connection handshake involves haggling over the rate and then each request costs a fraction of a cent. This would remove the need to de-anonymize users, likely kill the ads business and virtually eliminate DDoS/sybil attacks. It would also be an enormous vector for money laundering, and as a cherry on top make running a search and discovery services much more expensive. I do think the crypto grifters pretty solidly killed the credibility of this option.