I agree on all levels. I hope to have my Audion SET 845 back soon. I want to hear a good SET in my system. I don't know the distortion level of SET. I thought SET had distortions also, but they were even order, not odd order. Even order being perceived as pleasing and odd as harsh. That belief is what I believe others with more education in the field say.You mentioned electronics harmonic distortion enhancing dynamics. The implication there is that at higher power draws, the amp will start to produce audible levels that boost this dynamics perception. But what about at low levels? I have found that SETs, for example, are more dynamic sounding even at low volumes where their harmonic distortion is low and completely innocuous. My point is that not all of the dynamic perception can be this distortion effect. Also, even if cleaning power and reducing distortion is technically "correct" ,if it lessens the emotional engagement of the music, is it a net benefit to the listener? BTW, I use a power regenerator and I find that it has only positive benefits. I have tried filters and some help and some do not...some kill the sound completely, where a regenerator on the same system works beautifully.
Filters are still the wild west. I have wondered about lithium batteries with a large inverter. You could make a system with equivalent battery storage to 2 Stromtank S5000 with an even larger single inverter for about $17K. That would be an inverter with 30,000 watt output . Inverter would be less than 3% thd. Heck, it could even be done fairly legally if it was truly stand alone with its own power strip.
At one time I looked into making a belt drive generator. A electric motor attached to a generator motor with a belt. Use a Frequency drive on the primary to stabilize the voltage on the output. Most power from hydro, wind, gas, oil, nuclear are a spinning turbine. The biggest hinderance I saw was finding a really good secondary generator core to make the new power. All those small units are made to back up a house or building. They are not designed for high sensitivity lab equipment. And, it would have to be a UL assembly that would cost big money to develop And the utilities require all sorts of labeling and disconnects to put a second power generation system on a property.
I do believe you need some amount of filters to get a stereo to its highest level. There is too much noise out there. How and what you apply and where is open to a lot of debate.