[Uptrenda]

Introducing the requirement to spend money to use the service would drastically reduce its value. It wouldn't be Tor anymore. Payments would make it easier to link identities and filter access to it. It would also mean not everyone could afford to pay for the service.

>and clients gave up most of their privacy for nothing.

Also not really sure how giving up privacy comes into this? Depending on how the scheme is implemented you can still preserve all the same privacy of using Tor with provisioning keys. E.g. you might use enclaves and keep verification hidden inside enclaves (so hosts cannot see the challenge protocol) or use zero-knowledge proofs to hide everything.

There may even be simpler algorithms since the certificate chain would be using something like RSA SHA256 (which have some neat math tricks to modify them more compared to other algorithms.)