So again let me underline what I said before, that this is more a "standard library" problem than a language problem. Conceivably, Python could adopt Readers/Writers into the standard library, but it's late now. Python 2.0 didn't have the requisite stuff in the library to make the idea work, so modern-day penetration would be low. Go and other recent languages benefit from experience, and by putting these things in correctly from day one, can move on to the next problems we'll discover in standard libraries. :)
Sometimes people ask why we need new languages, and I think "get a fresh start on a standard library" is at least halfway to a valid answer. Imagine if Java the language stayed exactly the same, but we could reach into an alternate universe where a brand new batteries-included standard library was written based on the language as it is now. It would still be Java, but it would be a much better Java, with better interoperability between many currently-separate worlds through standardized, sensible interfaces and extension points, taking full advantage of lambdas, probably dropping the stupid synchronization stuff even if it is nominally in the language, etc. I think the end result is still something I wouldn't love, but it would be much better. But one can only dream about that.