I do agree with your post, IP theft/plagiarism is a serious issue, which we must not underestimate.

But I think Steem or Dtube don't really add to the problem. It has been possible for so long to copy movies, books and music, and there are companies fighting this.
By following accounts, retrieving IP addresses and getting information from ISP's they have already closed quite a few sites down.

I don't see anything different here, they will most likely shift their gaze here once it's really growing.