Apple invented the non-standard "viewport" meta tag and gave guidelines on how to use it [1]. The article that has popularized the term RWD mentions iPhone four times [2]. For me it is obvious that RWD started from the iPhone, but maybe our viewpoints (or viewports) differ.
[1] https://developer.apple.com/library/archive/documentation/Ap...
[2] https://alistapart.com/article/responsive-web-design/