The burden of proof is on Slat, and a report is not a proof. Until now, there's nothing effective.

In general, I think there are a few factors for comparing different solutions:

  - effectiveness
  - cost-effectiveness
  - scalability

Now, I'll put this in the opposite perspective. What is people doubting about the coastal cleaning approach?

Effectiveness? A large part of the sea garbage ends on the beaches. Is that considered not enough?

Cost effectiveness? There's no way machinery on the oceans is going to be less expensive than on the earth.

Scalability? Same as previous point.