Because not even professional linguists would be able to keep up with that, or even want to deal with it. The field is huge; anything language is Linguistics. For example you might be well informed in one specific field, but unable to even parse info from another.

Linguists often have a big disdain towards academicism, since they’re dealing with something that most people in the world do - use language.

And for the laymen, well… the sub is not for them any more, period.