Perhaps read more widely then take the quote marks out of that question. How FIR works is widely known, and any idea that it is artefact-free is not realistic. Consider how pre-and-post-ringing are going to sum in one ear, when the deconvolution has been done for the other ear. Then also consider how humans can discretely perceive direct sound and summed reflected sound, and how the direct sound is affected when time-based corrections have been made for the summed sound — or vice versa.
I don't think that how FIR works is "widely known". As a BScEE I learned about FIR during my college education but I had to learn more later on when I needed to use it in practice - so it's defintely a no, the way how FIR works is not widely known.
Take you, for example.. You don't seem to understand the difference between FIR and IIR filters. You also don't seem to know there are minimum-phase and linear-phase FIR filters, and that in the case of former no pre-ringing is introduced at all. You also don't seem to know that correction of speaker's phase doesn't affect it's amplitude response. Finally, you don't seem to understand that amplitude and phase correction equally affect direct sound and reflected sound, meaning that if you, for example, apply a filter to a speaker and then measure it's spinorama curves again you will find that ON, LW, ER and SP are equally affected by the filter.
Btw, pre-ringing and post-ringing do not "sum", they are perceived separately and while the latter is masked with the signal the former is of course not, so use of linear phase filters and/or phase correction should be done very carefully in order to avoid audible pre-ringing.
I advise you to read
this post where I explained and showed pre-ringing and post-ringing effects with minimum-phase and linear-phase FIR filters.
P.S. I especially liked the part when you said "deconvolution has been done for the other ear". Do you care to elaborate what is that exactly supposed to mean? Are you aware that convolution is a process where input signal is multiplied with filter impulse response? So, in that context, what would "deconvolution for the other ear" mean?