I've only got the stereo remake of Bartok 3 (on CD) with Kertesz & the LSO, which is pretty good too. Has the mono OSR appeared on Australian Eloquence I wonder? I still regard a recital by Katchen as the finest I have ever attended, he was a fabulous pianist. No doubt the OSR like French & Russian orchestras became more "international" over the years but it was surely the 60s VPO who had the sourest oboe.
I have a few HMV Melodiyas, a wild and exciting Tchaikovsky 4 from Svetlanov (wished later I'd got 5 & 6 too). Revolutionary cantatas for the Party by Prokofiev, complete Swan Lake on 3 LPs from Rozhdestvensky, Scriabin symphonies and the boxed set of Shostakovich symphonies. They really were unique and quite unlike Western European or American performances.
Decca of course chose Geneva's Victoria Hall for their first stereo experiments after electronics engineer Roy Wallace was recruited to head up the company's move into stereo. They had just taken delivery of their first two channel tape recorder, Wallace built 2 playback amplifiers, rebuilt a mono mixer for stereo use and a pair of 'speakers were cadged from Tannoy. Their Rimsky Korsakov Antar made in 1954 was the first stereo recording made in Europe ever to be issued commercially. It still sounds pretty good (Decca Legends CD) and according to Wallace Ansermet was greatly impressed when he heard a stereo playback for the first time.
The Decca sound from Geneva did vary over the years as Wallace experimented with different microphones and microphone techniques. For me Ansermet's two greatest recordings are the stereo Falla 3 Cornered Hat, and a compilation of Bolero, La Valse, Sorcerer's Apprentice & Honneger's Pacific 231 which was the last recording made by Wallace before he left Decca. Fabulous performances and wonderful recorded sound (on both CD and LP). I could also add Scheherazade (both R-K & Ravel), Chabrier's Espana with the greatest trombone slide ever, Debussy, Tchaikovsky ballets etc, but perhaps not so much the Austro-German repertoire.
On the rare occasions Ansermet recorded outside Geneva, the sound on the Classic Records Living Stereo facsimile reissue of the double LP of ballet excerpts recorded by Decca with the Covent Garden Orchestra is simply stunning (and to the best of my knowledge has never appeared on CD).
Listening to these and early Kingsway Hall stereos whether on CD or LP shows how recorded sound has not advanced over the years despite (or because of) modern technology.
While I respect your view based on the subjective listening at home, my experience have revealed that "modern technology" has advanced the recorded sound, particularly with SACD. However, one needs a combination of a hi-end equipment with the appropriate listening room to get the optimum of today's recorded sound.
Despite I have fond memories of the LP era in my subjective listening experience, I am quite satisfied with the modern products of labels such as Praga Digitals, Exton, Channel Classics, Pentatone, Challenge, Harmonia Mundi, Ars Production, etc. At least the tone, the pitch, the dynamics and the ambience (this feeling of space, where the music is performed) are as close to the real thing as it can get.