It's true that Google said " ... over time, we may decide to strengthen [the prioritising of HTTPS], because we'd like to encourage all website owners to switch from HTTP to HTTPS to keep everyone safe on the web." And you're right that it's easier to sort out now.
But, realistically, is it likely that the vast majority of site owners will take any notice of it? Will the millions of bloggers and small businesses and part-time website designers even know about this? And how many will have a clue as to how to go about it?
And, if that's right, would Google jeopardise the quality and relevance of their search results (which is, ultimately, what their empire is based on) by skewing them in a way that is, frankly, not relevant to most searchers?
Sorry, this is getting off-topic. Perhaps we should be having this discussion in the other current thread on this subject. But you were asking what effect the move to HTTPS would have on duplicate content. I was simply giving the opinion that you might be better off staying with HTTP.