Aliph, I'm not sure I would agree with the OP -- I don't think many people today would know the term. The last time I heard it used in pop culture was in the '90's. The movie is all but gone and the concept behind it is hard to implement - especially among friends!
I have a soft place in my heart for "Gaslight". One college term I really went out of my way to get home at the end of the term as early as possible, a lot of effort to get home and when I arrived ready to celebrate I found out all my friends would still be a day or two before they arrived. Ugh!
So I sat on the couch depressed and complained to my mom about the problem and I told her to top it off the only thing on TV that night was some stupid old black and white movie called "Gaslight". She told me to watch it, that I would enjoy it. At 19 years of age, how could I enjoy an old movie in black and white?
Well I did watch it, and that movie opened up a whole world of wonderful old movies to me that I enjoy to this day :-)
Now my kids wonder if my TV shows anything in color at all!
Bluebottle - gaslighting someone has a subtle shade of meaning, the deliberate approach, the implied relationship, the cruelty. But it is certainly not a necessary piece of vocabulary, that is why I had thought that without the film the concept was nearly gone.
Aegis - your comment about the oligarchs certainly rings true but I just don't remember the use of the term during the election. Who was saying the other side was gaslighting who?
Could the rise of the term be a sign of the rise of the Turner Classic Movie network? They claim to be doing well with a young audience. Or is that theory silly?