I think the conversation is about other limits instead of account creation, like limits for creating content on the blockchain, curating and possibly flagging as opposed to curating (upvote/downvote).
It's a very hard conversation because people intrinsically see limits as counter to freedom, especially when you start talking about pegging account to a metric which dictates what they can and can't do with on the blockchain.
I think it's necessary we look into that direction, limits over how much we can post and the frequency are already built in, we can build in other limits such as a metric that determines if you can create content, if you can curate content, and if you can flag content. That way policing the community doesn't resolve around the pseudo flagging/hidden we have, but actually revoking people's privileges to interact at the blockchain, just as in real life we have certain givens, so on the blockchain we can have certain givens, one being to create content, yet it can also be removed were that person to spam, or plagiarize, especially if it's exclusively what they do, so if the community decides that person A is not a responsible curator, they could have a say over a metric which has a value that determines if an account can or cannot curate.
That's fresh thinking on the matter, and exactly what I meant when I said someone else besides me might have ideas I couldn't come up with. I am aware that, in principle, the economic constraints on Steemit that cause new accounts to need to be delegated Steem in order to make posting possible, are mechanisms that might potentiate such limits as you discuss.
I'm not sure of details, but that may be the right way to handle spam and plagiarism. At least it's an avenue that has potential.