Apparently it is gaining traction. For example, the Tensorflow project is working on building a next generation library with Swift - https://github.com/tensorflow/swift
Only because Lattner is part of the Tensorflow team, and they still don't have a solid story regarding OS support, in spite of several people pointing out how much better supporting Julia would have been.
Which incidentally also supports Windows out of the box.
Thank you, the second link you provided was an extremely interesting read. It seems to me that Swift has reached a level of maturity where the language and the ecosystem can now exist independently of Apple’s support.
You can read why here - https://github.com/tensorflow/swift/blob/master/docs/WhySwif...