Have to see if I kept the link to an article found on the web years ago about front loading washer designs and water efficency.
One of the things covered was the fact that once machines begin to go below a certian water level various systems need to be developed to aid in moving water through laundry. All front loading washing machines work on the principle of washing laundry by dropping it into a pool of concentrated water/detergent; and to and extent against other laundry/drum of the machine. However with very low water use this is not possible easily as there is too little water for "dropping" into. Article went on to explain about various coping systems to over come the problem such as spray injectors.
Spray injectors were used in front loading washing machines long before LG came on the scene, with even some commercial units having the feature. Problem is the more "features" one introduces to a front loader, the more complicated it becomes which drives up the cost of an already expensive design model.
Rinsing is a process of diluton, and even spraying water at the wash isn't going to help much with low water levels. This is why even when the wash cycles may be skimpy with water, rinses usually get a tad more water. There is also the problem that front loading washers are VERY sensitive to excess foam. This means detergents need to be rinsed out throughly if proper rinsing and spinning is to take place. Otherwise the machine simply will not be able to cope, not spin, and leave one with wet and soapy laundry.
There are many ways to rinse in a front loader, some more water hogging than others. My Miele uses two or three deep rinses with no spins in between to dilute detergent out of the laundry. There is one quick 30 second spin between the third and forth rinse, then a long high speed spin after the fourth rinse, then another final rinse before final spin sequence. By "deep rinse", my Miele does just that, using the default water level for "Delicates" which has water nearly 1/4 up the window. IIRC each rinse uses about 10-12 gallons of water, maybe a bit more. However when combined with the proper HE detergent, all but the most over soaped loads are cleanly rinsed by the fifth and final rinse.
Now many modern front loaders will cool the suds, drain, and go straight to spin, then one, two or three rinses with between spins and or spray rinses to force detergent out of laundry. How effective this is again will depend upon several factors including load size in relation to water levels, and detergent used.