In the long arc of computing history, each new form factor has arrived before the world was ready for it — and the companies that survived were those willing to wait. Snap Inc., buoyed by a stronger-than-expected quarter with $1.6 billion in revenue and 493 million daily active users, has chosen this moment to stake its future on augmented reality glasses called Specs, priced at $2,195 and launching September 16. Evan Spiegel is making the case that the next great computing platform will be worn on the face, not held in the hand — a conviction that is either visionary or premature, and perhaps