Perhaps you should have quoted the comment you was referring to in order to avoid confusion.
As you didn't answer my question I shall answer it for you.
No, a motor is not 100% efficient throughout it's rev range and as such has a power curve.
That power curve has a a peak and at that peak it is it's most efficient. When a motor is running at it's peak it is putting the least amount of strain on the electronics involved.
To get the most out of a power system it is advantageous to have an esc that runs that motor at it's peak.
My statement of an esc being designed to run at around 92/95% refers to designers taking a very educated guess that on average a motors peak is around the 92/95% mark so at full power the motor is running at it's peak.
When a power system is not running at it's peak it generates heat and heat causes more inefficiency. Of course a bigger esc than needed is perfectly fine and will run all day but the motor might not ever be run at it's peak performance and your batteries might not be getting every last second on run time otherwise possible.
Obviously there's other factors like no load current when doing a dive for example but it's hardly a prolonged state.
Let me be clear here I'm not pretending to be be any expert on this I'm merely regurgitating others hard work much the same as others are.
I'm going off a thread on either rcgroups or runryder where a lot of testing with a trex was done and various motor and speed controls tested. The results being try to match your esc to your motor and really cells for that matter, as best you can in order to get best performance from them.
Having reread the post you've quoted I stand by my statement of saying be careful on your selection because i beleive yiu should be careful selecting your powrr train however I did not quite realise I had said it WILL burn out, that was the wrong thing to suggest and I do in fact take that back.
To be accused of spreading falsehoods and possibly causing a lot of harm by doing so is just preposterous, you might visit a forum to cause an argument but I visit to try and help people whilst getting bits of help myself. I post what I believe is right just like everyone else on the forum. Sometimes things may not be worded perfectly all the time by me or anyone else but the intention of trying to help is still there so I find the insinuation that I'm intentionally trying to derail people and maliously posting incorrect information extremely offensive.
I may have over-exaggerated the consequences of being wrong here. It is just a hobby. However, I am going to argue that if you are wording things incorrectly it doesn't matter what you know or don't know, what matters is how the reader interprets it. From my end it looked a lot like you were talking about things that, according to what I've learned in EE, make no sense. Additionally, I never "insinuated" that you were "intentionally trying to derail people". Actually I believed the best in you, that you simply were doing it by mistake. It happens to the best of us.
There are a lot of great people on forums doing great work to test motors, and it's true that motors have an efficiency curve, but ESC's have little to do with choosing an efficient prop/battery setup as long as it can handle the current and the voltage/cell count. To be honest, I'm not sure what you mean when you say "My statement of an esc being designed to run at around 92/95% refers to designers taking a very educated guess that on average a motors peak is around the 92/95% mark so at full power the motor is running at it's peak." I'm not sure if you are trying to say
the ESC needs to run at 95% of the ESC's peak current handling (a very wrong statement) or
the motor should run around 95% of it's peak efficiency (I can see an argument for this one). He asked about an ESC's current rating and you gave what I would consider to be bad advice based on an auxiliary factor (motor efficiency). That's why I called you out.
