I think the recent innovations in sail technology on commercial ships have less to do with the fact that they use the wind, and more to do with the fact that they're now more reliable and easier to operate. Using traditional sails might have saved just as much fuel, but would have required a large crew always on call to operate the sails. For large cargo ships, you'd probably have to double the crew size, which is extremely expensive. Now the deck officers can control the sails and almost everything can be automated.