The air in a ram-air air-beam is not fully free to escape. Ram-air pressure prevents escape from the front and newer sled designs are now sealing the rear of the cell. Of course, parafoil cells are usually aft-sealed too, but lack the “splint” [WP].
The analogy is for those who can see the commonality. As for scaling, a valved ram-air airbeam is predicted to both out-scale an airbeam dependent on a flying air-pump system, as well as be simpler and cheaper. The empirical evidence is the preponderance of ram-air kites, but lack of self-pressurizing-aloft airbeam kites.