Clearly we don't capture or archive much of what's produced now, but that's not a new thing. There are very few records of things from more than a couple of hundred years ago. If you want to see anything that isn't the official government's (or monarch's) line there's much, much less.

If you ignore digital media, and compare the number of physical books produced, there are many thousands of times more produced now than there were 500 years ago.

You're right in the sense that a lot will be lost, and that we should strive to do better, but in terms of comparison to the past we're preserving an exceptional amount of knowledge.