No, the key reason as to why Porsche offer an AWD 911 is because the technical layout (where the engine is mounted aft of the rear axle) allows them to. Because the gearbox in a Cayman is located behind the mid-mounted flat six, getting a propshaft back to the front axle would be practically impossible.

I think that Porsche intrinsically understand the benefits and compromises of RWD vs AWD, and the reason that AWD is offered in 911s is to increase their everyday useability - especially in changeable conditions - and not necessarily as a nanny to unskilled drivers. PASM is for that.