Greatest ever, or of a given time period, is ridiculous because this isn’t an athletic competition. I am not disputing any points you make about Richter, but I don’t know how to compare him vs Arrau, Pollini,Kempff, Casadesus, Michelangeli, Horowitz, Kapell, Argerich, Volodos, Kissin, Berman, and about 1000 other names that I could pull of great artists that had less well known careers .
Part of Richter’s mystique was that he worked on the wrong side of the Iron Curtain. His releases to the West were sporadic, dependent upon the whims of the Kommisars. So his virtues were largely tantalizingly out of reach for decades.
When the floodgates opened there were hundreds of recordings available. Many of them were from the dog and pony show life that Richter favored, driving around the byways of France with an upright in the UHaul, stopping in a small venue on a whim, having an impromptu concert. A “happening “. It would have been really cool to be having a glass of wine in a courtyard in a small village in Provence and have his merry caravan suddenly pop up, but many of these recordings were made with out of tune pianos with mikes stuck God Knows Where (he was notorious for not wanting to be bothered by recording apparatus). The sheer ubiquity of these one offs dulled the luster for me, a bit, especially as he was audibly past his prime-but still pretty awesome.
So I am not disputing his stature, as as a recorded artist, I don’t know how to rank him vs fearsome competition, nor I do I wish to even consider it a competition