Referring to a curve with a derivative everywhere equal to its value as something that has an end gives the game away: pure fanciful nominalization with no grounding in any kind of concrete modelling of any constraints.

IMHO this is really silly: we already know that IQ is useful as a metric in the 0 to about 130 range. For any value above the delta fails to provide predictive power on real-world metrics. Just this simple fact makes the verbiage here moot. Also let's consider the wattage involved...