'It's harder to accomplish this in a "air conditioned" air terminal'
Is actually not harder, it's just that no one can be bothered to do it if the terminal space offsets the airframe utilization. Also, while it does reduce complains of boarding/alighting time it increases complaints due to the walking and/or bussing.
If you look at old photographs of LAX, from before the build the ground level connectors buildings, planes would pull up parallel to the sides of the rotundas and a jetway connects both in front and behind the wing. Some of the west remote gates still operate like this, where a very large plane actually connects to two remote gates. Currently, LAX TBIT has gates with multiple jetways that can meet multiple doors in front of the wing as is done in many other places with large planes with high-prices premium traffic. (The jetwways are often split between first/business/economy classes.)
Some airports AMS and even little ALB have dual jetways where one extends over the wing. However, AMS has had incidents where the jetway has struck the upper surface of the wing causing damage.