alt Hacker News1) But for many people and in many situations, translation---including MT---is good enough. And that overcomes any perceived need to learn another language (which learning may be in opposition to learning something else, something perceived as more important).
2) Most people don't "consume" literature or poetry, and it's unclear to me that non-performance art requires language. (I appreciate Rennaissance painting, but apart from the occasional Latin writing I don't need language to understand it.)
Disclaimer: Besides English, I'm reasonably fluent in Spanish (more so 35 years ago when I last lived in a Spanish speaking country), and used to be reasonably fluent in German, French, Tzeltal and Shuar (and a bit of Italian and written classical Greek). So I have every reason to hope this study is correct. But I have my doubts.
Translation is good enough, but quite often no translation exists. MTL is at this point good enough for simple texts and for everyday living like restaurant menus and shopping, but any even mild complexity in a text, like long-running context (necessary for consistent translation of terminology), puns, purposeful ambiguity, etc., MTL is completely unable to cope with. It just doesn't work and it will likely never work.