[RC-Monster Mike]

Those numbers are meaningless, Artur(72A and 30 amp). The watt output is simply a function of voltage x amperage x efficiency. You don't necessarily need 72 amps to get the power from a 2800xl motor, nor will the 1930/8 produce 1200 watts at 30 amps unless it has serious voltage(40 volts to be exact - not counting efficiency losses!). I am talking real life here, not the information you can read and interpret many different ways.
Many people read those amp numbers and get the wrong idea. They are mostly meaningless for this discussion.
My comparison is based on a similar Kv motor, with a similar size and a similar winding construction in a similar application with the segmented magnets being the primary difference. The results are simply that in the r/c car application where partial and varying throttle is used, the segmented magnets simply perform noticeably better. The non segmented rotor may show similar efficiency on paper, but in partial load applications, it is simply not as efficient as a segmented rotor. The non segmented magnet will produce high efficiency when used at their optimum amp draw and voltage (when used in an airplane at a constant throttle, for example, there is little benefit to a segmented magnet), but as you already mentioned, the efficiency is not linear and is/can be significantly lower than their stated values in a car/truck application.