Was that the goal? From what I read Envato mainly wanted to get the reviewing queue down. Items are reviewed one by one and they’ve noticed that a considerable number of authors submit a lot of un-approvable items at once. Those items stack up in the queue and by the time they get their first hard reject, they may have a lot of similar uploads just waiting to score the trash can. By limiting uploads per queue cycle, those authors will have some more time to work on their material, from the point of the first hard reject to the point where they upload again.
I don’t think the copycat issue is the primary target for the new limits, and I don’t think we’ll see less of it as a consequence. If I understand correctly, the number of authors submitting is the same or increasing, and they recently hired more reviewers. Limiting the items in queue does not necessarily limit the number of approved items per day. On the contrary, if this all leads to more authors learning what it takes to be approved, we’ll actually see MORE copycat items as a result. The only thing that can stop low quality to hit the market is to narrow the scope of acceptance.