So I think your original post is therefore referring to conductors prior to the 'jet-set' conductor era, when conductors lived in the cities of their orchestras. Those were different times and certainly the standards of orchestral playing was nowhere near as high as it is today. That said, I still think Andreas Blau's views are relevant insofar that he was commenting on the standard of present day conductors when compared to those from the past, which since 1969 when he was first appointed at the BPO, would have contained virtually every single conductor of note active from that time onwards.

As for the 'believers', there can be very few left who would have seen those figures from the 'golden era' live, so I hold their views with a degree of scepticism, although would concede there seemed to be many more fine conductors active in the past than now. Certainly it would have been extraordinary for one conductor to hold simultaneously the posts of principal conductor of both the Chicago and Concertgebouw Orchestras in bygone years...