There were a lot of great pianists during the 60s-70s, yeah. A few into the 80s. Haven't been impressed with anyone since, though. A few strays here and there. If you're fine with the pianists you're familiar with, then that's good.
It got better in the '60s and '70s, THEN began to get progressively worse
It was still at an acceptable and even great standard in the 60s and 70s, but even by then we had seen a decline, especially in French and German signing. Italians managed to hold onto things for much longer.
And even then, only when considering the repertoire essentials
Yeah, sure. I mean, there's not really any competition considering most people weren't performing Rameau or Handel or Enescu back in the 60s and 70s; so we make do with what we have, and the music trumps everything else anyways. But I would still kill to hear Rameau sung in the traditional French style which completely died out after the 1950s and which can only be hear on antique recordings.
Besides, as they say, Barenboim is Furtwanglian anyhow!
They're very different. Barenboim apes Furtwangler's tempo fluctuations without care to much of anything else.