I would guess that most outdoor speakers are sealed cabinets, and a sealed design generally yields a higher -3dB point (look at Outlaw's sealed LCR and compare it to the ported BLS for a very clear example of this principle).

Outside is a big room, so it's hard to pressurize the way you would with a subwoofer in a room. I recall a debate some time back (probably last year some time) here in the saloon where someone was in search of outdoor surround sound and found some outdoor subs. They were passive subs with separate amplification, and they were pricey. As for a full range speaker, how low do you want to get to reach "full range"? After all, even indoor speakers can rarely get below 25Hz or 30Hz without a powered sub to assist them.