I think you're saying, how much other good content is out there that I'm missing out on because I only read English, and it's a good point.

However, English has become the (now ironically named) lingua franca of, at least, the more educated parts of the world, and many people who are most comfortable in their native languages are still often translating their best work into English in order to see it more widely read. This is often the case with scientific papers, for example.

Perhaps England's biggest gift to the world was its language.