If you were tasked with putting together a message to send to space aliens, with the only restriction that the message had to be under 4GB, what would you send?
So you could do text-only Wikipedia and probably compress it. Maybe drop a few thousand of the articles that don't matter or are stubs. Drop all the entertainment articles, etc.
I don't think you appreciate how much text you can fit into 4GB. The first entire gigabyte could be dedicated to various means of translation and explaining our language system, and you'd still have a 500 million words left after that.