I have no doubt that there is the potential for conductors to be great. For me the issue is mainly one of time;

Time for a conductor to develop technical skills, interpretative insights, relationships with orchestras, enough rehearsals to refine performances. We live in an age where gratification and impact need to be instant. Where major orchestras are willing to share Artistic Directors with more than one other orchestra from the other side of the world. Where audiences want maximum "bang" from the performers in front of them as soon as possible.

I think that many orchestras would get "bored" these days too if they had the same person on the podium for days and weeks on end going over the same kind of pernickety detail. Orchestras are now so good that they can pull a perfectly decent performance out of the rehearsal hat with just about anyone in front of them.

My guess is that some of the most rewarding concerts (and probably rehearsals for the players too!) are taking place around the world in nominally 2nd tier orchestras with lesser known conductors where modest finances mean that fees are relatively lower but possibly there is more time and willingness to explore even standard repertoire.

What sums up for me where the world has gone wrong is how a still-young conductor such as Andris Nelsons can be principle conductor in Boston and Leipzig and already have complete cycles of Mahler, Bruckner, DSCH, Brahms, Beethoven etc etc and no-one from the record labels or orchestra managements seem to be questioning their artistic worth. There is simply not the TIME for Nelsons to have really developed a deep understanding of that amount of music with those orchestras. They must be skilled read-throughs of superficial interpretations. But the reality is that even for a conductor in demand as much Nelsons how many times will he have actually conducted some of these big works before immortalising the performance on disc. I suspect if you spoke to the older generation conductors (who in the main had much smaller active repertoire they conducted - that's another story) they would say they didn't really dig under the surface of a major work until they'd performed it at least 20 times or so.