"So far as we know" is the key phrase, because we know so little. It's true that plays were seen by many as ephemeral, and quite possibly Shakespeare buggered off to Stratford with a full purse and a sheaf of property deeds, happy in the thought that his literary immortality had been assured by The Rape of Lucrece. It's also possible that he knew his plays' worth, though, and put arrangements in place for their eventual publication in the First Folio - a move that may have been encouraged by the sight of your man Jonson's preparation of his own folio Works. (Jonson got mocked for his pains, but perhaps because he was publishing himself as much as because he was publishing plays.) What's indisputable is that the company thought Shakespeare's plays sufficiently worth preserving to keep the texts not just of the perennial favourites that might have been revived at some future date but of superannuated pieces like 2 Henry VI and uncommercial oddities like Timon. Perhaps Loves Labour's Won ended up as pie-bottoms, but quite an effort seems to have been made to preserve the oeuvre entire. Who's to say that the effort was not in part Shakespeare's - a man whose concern with literary futurity is amply evidenced in the sonnets?

That's not to say that Shakespeare adopted temporal and geographical vagueness as a conscious futureproofing strategy. Of the three "perhaps"s I list in the entry this is probably the least likely. But neither do I think it impossible. He was a subtle chap.