I'm still trying to find another sci-fi show/series/episode - it has similarities to the one Twilight Zone with the experimental aircraft (And When the Sky was Opened). But in this one, a bunch of scientists stumble onto ideas that put them on the track of what amounts to a Grand Unification Theory that explains the fundamental physics of the universe.
As each of them begins to understand it and see what it means, they end up vanishing and no one [outside the remaining team members] remembers them until eventually, the story ends with a janitor sweeping the floor of a now-empty laboratory. I recall there was at least one woman on the team and I seem to remember it in black-and-white.
(In the Twilight Zone episode, it ends with a different headline about the crash in the desert - so the crew is all remembered again, but with a different end-result. In this one, the people were entirely erased from existence for figuring out the secret of the universe)
I recall one of the premises is that when the first scientist realized the implications of the new theory he is amazed that no one had put the pieces together before (which kind of sets you up for the result).
I can't remember what series/show it was from and can't seem to find it anywhere! I'm starting to think maybe the episode itself was wiped out of existence and I'm next because I still remember it!