I disagree. I don't like the way the power of the word has been eroded either, but gaslighting in the original sense does happen, and I think parents are frequent offenders, because they become accustomed to the power they have over their kids' perception of reality.
The most extreme example I know of: a woman I know was sexually abused by a teenage neighbor when she was very young. When her parents found out, they told him he wasn't supposed to do that, and when they caught him again, they uninvited him from their house for a few years, then welcomed him back, and scolded her for being "rude" and "dramatic" when she cried and didn't want to be in the same room as him. Now, before you get suspicious, that previous sentence was her parents' version of the story, which she accepted for years. So this guy was in and out of her house almost her whole childhood, treated as part of the family. Her mother even showed her the "very nice" note he sent declining their invitation to the party they were throwing for her college graduation. When they got on Facebook, they immediately friended him, so he got all the family news they posted, including when and where she moved, the new jobs she got, etc. They called her paranoid and self-centered when she asked them to stop sharing all the latest about his life with her and vice-versa. The family narrative growing up was that all of that was perfectly healthy and normal, and she had difficulties with it because she was a difficult, dramatic, and irrational person, the kid with all the problems who spoiled things for her otherwise perfect family.
So that's already gaslighting on an emotional level, but if you want it at the factual level, they covered that, too. As she started talking to her parents about it as an adult, it dawned on them that what they did looked bad by "present-day standards," and they started changing their story about what happened. In their version now, they banned him from the house after the first offense and didn't allow him back until she moved out for college. They never scolded her for being "rude" when she was scared of him; they were sympathetic. Her mother even tried to say she arranged counseling for her, and then backed down and said, "Well, people didn't get counseling back then [the 1980s] but we did the equivalent," by which they meant talking to the priest at her school about her "emotional problems."
That's pretty legit gaslighting when you're in your thirties and suddenly your parents change the story they tell about how they handled your molestation, after sticking to the previous story for a quarter century.
Not only that, the ease and lack of conscience with which her parents changed their story made my friend wonder how much of the version she grew up with and took for granted was fictionalized. She doesn't really remember how many times the abuse happened, what period of time it spanned, who put a stop to it, or how or when her parents found out. She has a few fragmented memories of certain times and circumstances that she mostly trusts, and the rest was secondhand via her parents.
I could tell you other stories about parents misremembering things to their own advantage, probably unwittingly in most cases. I remember my sister screaming and crying and slamming doors about our parents not letting her go to a certain camp one summer that she had been to the previous summer. My mother's memory is that it was my sister's decision and she didn't want to go the second year. I don't think my mother is consciously lying. People's memories change over time, usually in ways that protect and flatter them.