Further, unless I'm missing something, I don't feel like structure concurrency can fully replace everything offered by (NS?)Lock. Perhaps even a little with OperationQueue and Timer. I admit I don't understand RunLoop enough to make a judgement there, but expect that it might be similar.
To be clear, I use and prefer structured concurrency whenever possible. It just seems that it doesn't quite offer a complete solution. Yet, at least.
edit: I appear to just be echoing @Jon_Shier's sentiments 
What’s next for Foundation - #3 by Jon_Shier - I'm excited by the announcement otherwise, though!