Because the reason why https://en.wikipedia.org/wiki/Hashcash wasn't useful for anti-spam after all is because attackers have access to the cheapest compute in the world: botnets and devices that aren't their own.
Because the reason why https://en.wikipedia.org/wiki/Hashcash wasn't useful for anti-spam after all is because attackers have access to the cheapest compute in the world: botnets and devices that aren't their own.