I don't have complete grasp of effects of this sort of power factor, but do realize it is a distortion PF and is different from displacement PF like you get from motors. If it typically has a leading effect instead of a lagging effect then that is likely why you don't hear much about trying to correct it as it would have some cancelling effect to the motors that are still causing bigger issues for the POCO's simply because there is so much more motor load on the system.
Switching power supplies are becoming prevalent. You hear complaints about data centers.
In a DC switching power supply the LED will be connected to a capacitor. There will be a sensor too. Hall effect, shunt, or voltage divider. That’s the back end. The voltage/current regulator pulses an SCR or MOSFET on and off to regulate output current. So the AC line side sees a capacitor. Current draw looks like “rabbit ears”. Depending on phase angle it can appear resistive, capacitive, or resistive but highly nonlinear.
Utilities are concerned with transformer load. With true sine waves they are concerned with total amps (kva) because all a transformer sees is amps. There are switching arguments too but amps is the key. So we bill on kw but load is kva.
With harmonics this still applies but in other ways. Not all harmonics are equally bad. VTHD is universally bad. This is high when harmonics are saturating the power delivery system causing “brown outs”. Current is rated on ITDD, current demand distortion. This is measuring current harmonics as a percentage of transformer capacity. If we aren’t near capacity even if current harmonics are horrendous voltage is unaffected and we don’t care. It’s only at capacity where current harmonics temporarily push the transformer to the point that it causes voltage swings or voltage harmonics that it becomes an issue.
Solutions are dilution (as mentioned motor loads offset harmonics), bigger transformers and wiring, reactance, and tuned filters. Line length helps a lot since that is reactance.
With the growth of data centers utilities are used to it. As more motors switch to drives with PMDC even motors are contributing. A bigger local concern is undersized neutrals in 3 phase. Using full size neutrals is an easy fix.
Response to questions about leading/lagging: switching power supplies are like solid state synchronous loads. They can be either but low cost ones are simple nonlinear “rabbit ears” with 20% current %THD (nor ITDD). Thinking about it a little with a pure SCR design since those can only turn on at most firing angles it will be lagging or at least appear that way in the fundamental. It’s a leading load but since the SCR turns on after the voltage zero crossing based on current regulation most of the fundamental harmonic appears lagging and the rest will just reflect what the Fourier math does to such a nonlinear wave. Fourier math just isn’t really suited to PWM. Power factor on switch mode supplies is a square peg/round hole problem.
You can do leading PF easily with FET / IGBT supplies and enough modulation index.
