Come up with a way for siteops to block someone and all their sockpuppet accounts, without knowing the underlying identity, and you’ll become a billionaire.
Without that, the only option we have today is deanonymization, which is a terrible option. We ought to do better.
It's really just a matter of balancing the difficulty of creating a new "identity", so that legitimate users can occasionally use multiple identities to partition their traffic and make it harder to get doxxed, but are still deterred from creating identities cheaply to engage in sybil attacks or escape blocks. There are various ways of committing real-world resources to an identity to deter such abuse. Actual meatspace identity is of course one way of doing this, but there are probably others.
What you are assuming is possible is a logical contradiction. To be able to recognise two persons as being the same is in fact the definition of de-anonymisation. Please check your math.
I'm not restricting my considerations to "the technology that is implemented and available to Tor users today", given that what's available neither meets the needs of sites, nor the needs of users. If you think that the idea is inappropriate, please state so and make your case for why you believe in your viewpoint. If you think that the idea is impossible, please note why you believe that — and then consider the idea as if it were possible.
Come up with a way for siteops to block someone and all their sockpuppet accounts, without knowing the underlying identity, and you’ll become a billionaire.
Without that, the only option we have today is deanonymization, which is a terrible option. We ought to do better.