This picture (to my eyes) is about verifying the cooling performance of the product design under stress test. This manufacturer has said that they use outrunner motor inside the product, which means that the coils (stator) are inner parts of the motor (and rotor is outside). Stator is (typically) the part where the coils are and where heat is created inside the servo motor). Outrunner motor design is typically such that it does not have large heatsink or surface by its design that would keep the motor parts cool enough without some active cooling. As I understand it, this mfg. has added also some layers of casing material that affect so that without active cooling it would make the temperature of the motor coils and parts too high so that product life / reliability could be compromised. Therefore verification of the cooling design is actually needed for them (so that the motor can be run on the torque level they use it under all the layers of material).
The psu power drawn in picture is such that 25 Nm is the max power in stall situation, then in the first 3 minutes the torque is lowered linearly to about 20Nm. The previous means that needed electrical power is lowered by ~36%, then again after perhaps after 13 minutes the torque is lowered to 15Nm, which represents about ~36% power requirement from the psu ( or 64% reduction from peak power which may be the overall cooling power of the product design so that the motor does not overheat inside of the product in long use sessions).
Inrunner motors (when the motor is correctly chosen for the task) do not need active cooling in this use case as the motor’s design itself is good enough to keep the temperature of the motor cool enough in this use case, (barely even warms, considering how hot the motor is designed to run). Moreover, advertising stall torque is actually irrelevant in this use case as nobody hangs in the corner for several minutes, (as far as I know) there are no such turns in real race tracks that would require a driver to turn the wheel with let’s say 15Nm of torque for 15 minutes. Quite describing title of the picture to my eyes could be something like “verification of the product’s active cooling performance under stall torque test” which in engineer’s mind also translates to, “how many watts of heat the product’s active cooling design can cool the product under use and with known fan characteristics”.
So, basically as we have had no use for these sort of graphs / tests in our product design process, we have not made such graphs and likely will not make these as these seem more or less irrelevant as we have passive cooling and different objectives in our product design.