Well, yeah, but that's like saying that producing a tree of pomaceous fruit hides the fact that citrus fruits exist.
reply(Yes, I did make an apples and oranges joke.)
The tree appearance just makes it too inviting to imagine PIE as some pristine ur-language, the kind of original language of Babel. I'm not saying that people explicitly think these thoughts, just that it's easy to get this impression, even if it's not conscious. The fascination about the original human tongue in Eden used to be a common intellectual preoccupation. My point here is that PIE is quite a different story.
replyIs it though? It's not as if it can pull in hypothetical superfamilies like Nostratic. It's not saying it's a family tree of all languages, just I-E. Your assumption is that somebody would look at it and forget that Mandarin exists, or Arabic, or Finnish, &c. I don't buy that. Hence my fruit joke. I'm not sure exactly what you expect them to do to avoid an egregious misreading by somebody spectacularly smoothbrained, because anyone with that mentality isn't going to be paying attention anyway.
reply[Removed my Anatolian criticism: I just hadn't zoomed in enough!]
No, I understand that people would know that Chinese existed far away. My point is that locally, PIE had neighbors, had variants, dialects, it had earlier forms, it was like a living language in a normal human context.
replyMaybe your brain works differently. I had this kind of misconception, imagining languages to be Pangea-like. That there used to be less linguistic diversity, there was a big uniform language (and perhaps a handful of others far away on the Earth) that later on fractured. But reality is more dynamic. PIE was just an ordinary language. And there was likely more linguistic diversity than today, due to less communication and travel opportunities and geographical features being more isolating.