this is an increasingly common situation. it goes something like:

  - i have a free, niche resource
  - it becomes too popular
  - i make it more efficient
  - now it's really popular, and people are "abusing" it
  - let's make them proof-of-work
  - ... and proof-of-work harder
  - but now "legitimate" users can't use it
  - ???

the core problem is that the average person uses a mobile device where work is expensive, and the "attackers" use servers where work is cheap. if you require expensive proof-of-work, next comes a cheap-work-as-a-service where inefficient mobile devices pay small amounts of money to get efficient servers to complete their work for them. now everyone has an interest in making their usage efficient, but there's still an obvious inefficiency in the system: why have people pay unknown 3rd parties to burn cpu cycles to reduce costs for a free service, when you could just have people make small payments that cover the service's costs?

which is called l402/x402. micropayments' day has come