Conductors are a relatively modern creation. Up until Beethoven or so, orchestras did not have a conductor. They were lead by the first chair violin, referred to as the concertmaster or leader.

Many ensembles that follow historically-informed performance practice (e.g. Concerto Köln, Akademie für Alte Musik, and the Academy of Ancient Music) generally do not play under a conductor until they get into Haydn or Beethoven or Mozart. There are some HIP ensembles, however, that always have a conductor, like the King's Consort.

There are also some modern chamber orchestras that do not play with a conductor. The Orpheus Chamber Orchestra has never had a conductor, for example.

BTW, Karajan almost always conducted with his eyes closed. He wasn't especially skilled or showing off, it's just one of his many peculiarities.

Sony (who acquired CBS Records or Columbia, if you remember back in the days of LPs) released reams of Glenn Gould video performances on VHS and laser disc as part of the Glenn Gould Edition back in the 90s. I picked up the laser discs for a song at various record stores around the country right when DVDs were coming out. Needless to say, these haven't been re-released.

Watching this performance of the Goldberg Variations is a religious experience of sorts, although the jarring camera angle shifts do eventually get old. The CBC started recording Gould for broadcast on TV back in the 50s, and these performances, ones that could not be edited for perfection show just how talented he was.

Also, Gould didn't give up live performances because of his nerves. Rather, he simply hated live performances and wrote and commented on this extensively. He felt that the whole experience was degrading and that being in front of an audience was an impediment to presenting his ideal vision of a work. Tape and the recording studio explicitly enabled this.

One little bit of trivia about this performance: Gould's usual piano was a Steinway (CD 318), but it was irreparably damaged during transit when some movers dropped it. He made a trip to the Ostrovsky Piano Company in NYC to find a new instrument, but didn't find any that he liked. Before leaving through a back corridor, he spotted a much used Yamaha that no one wanted him to play. Needless to say, he tried the instrument and the rest is history. It's the piano he plays in this recording.