Hi mh,
no need to mourn at all. I will never dispute any well done interpretation at all. of course we have had in history in many centuries impressing musicians who knew to convince with exactly those musical means and instruments which were available for them and made most impressing music as well as interpretations as far we can still listen already in pretty much recordings we nevertheless hear to day for 99% through any kind of loadspeaker.
And of course I would enjoy as much a good performance with what instrument ever as soon it is convincing. The only imho "misbelieve" I try to put a bit in question is the assumption, that historic instruments are in any way per se superior. No for me they are not and there is a pretty simple reason, it is the musician and not the instrument who makes the music. It is the musical intenttion which searches for nuances not the wood or specific data who does that at any kind in any instrument for the musician.
It is true, that we presumably all learned to speak the language music with traditional instruments and our tradition is rich enough to teach us very very much impressing, important and deep things about music.
But guess what imho you even can learn, that there is from all th centuries of our tradition scarcly any greater Composer or musician still known who was not interested in exploreing and using the most modern instruments of his time, so if we would like to follow their great example we should learn to speak their language with our own words with all means available in our time just as they did in their time.
the questions about the significance of the life performance could Imho be consideredd more and more like the significance of the storyteller in the centuries after Gutenberg has introduced the printing press. Yes get a fairy tale toldby your grandpa or grandma still might have its own irreplaceable attraction. But sorry, you can't comunicate with how many however loveable grandmas and grandpas all the knöwledge and intellectual creativity good libraries have transmitted since they could be printed on paper.
Would I disregard or even want replace the lecture (in music - the performance ) therfore in any way. No of course not. But wake up the reality is, that the performance of a composition has already now not much more quantitative relevance compared to the amount of music which is heard through loudspeaker and the more orless digital way to get in it as the fairytale telling grandma for the litareature we know (oh I forget even she uses for lang times books she just read it loud instead of giving their version of the "authentic" aural transmission) and why did even she use this less "authentic" modern cultural technic? simply because it is more powerful and more precise and so our reading grandma is always sure their version is not less convincing told than the Version how the Brother Grimm printed it.
Yes to travel by foot is pretty good to keep an eye for all details of your travel, but the USA would scarcly ever had become the most plural and powerful nation if all ancesters of those who live ther today had remaind with traveling by foot only because this is regarded as the only traditional "authentic" technic to use. Come on guys, stay a bit more confindent about the great instruments especially VSL provides and we all use with great pleasure. They are new and yes they can be used to make good music. That is at least my strong personal opinion. And yes I confess I still comiserate those who are not open to use all the powerful means and technics which are available today to unfold their Ideas and express themself.