No, this additional front-wheel drive is probably not suitable for construction site vehicles. The manufacturer would have to invest in the extra 400 kg for the distributor gearbox, drive-shaft to the front and for fork- instead of stub-axles. In this case, the simple hydraulics would probably overloaded.
Apart from that, of course during the all-wheel drive phase, the efficiency would not be anything special either. Indeed, to be able to free oneself from a sticky situation, this simple to build and certainly also cheaper equipment, would seem to be exactly right. Perhaps one could compare it with an emergency- instead of a fully fledged spare wheel. And in normal operation, it falls on either by weight nor by restriction the efficiency.
Also in terms of cost is this, to be adapted to each axis auxiliary drive, just right for vehicles, not worth the extra cost for a "real" all-wheel drive system. One example could be mentioned here, the snorkel truck of a fire brigade, seldom have to go to the heavy ground but must have in case of emergency this ability, too. Press a button and the auxiliary system is activated.
There is even an additional benefit. After all, the system provides via the hydraulically driven wheel motors 50 kW power respectively up to 6000 Nm torque, what can drive the entire truck if necessary also solely as for precise maneuvering. The hydraulic traction assistant from Bosch is therefore more flexible in use than only by rotating drive wheels. 08/12