Perhaps "term" is the wrong, ahem, term.
Maybe you want "metrics"? There's lots of non-GDP metrics that could be used to track ai's impact on the world.
Instead of the failure mode of saying "well, GDP didn't track typists being replaced with computers," maybe the flipside question is "what metrics would have shown typists being replaced?"
I gather that the historical definition of slow takeoff is something akin to "grand GDP growth for several months in a row, due to AI advancements".
While recent advancements by OpenAI et. al. are impressive, sometimes people will claim they would never have awarded bayes points to slow takeoff for ChatGPT, because one of their primary contentions is that governments will prevent any AI that isn't politically revolutionary from making innovations in things like housing or medicine.
If this is true, perhaps there should be a new term, since it still seems useful to talk about a tech tree where we have very strong tool AIs, even if they're not making everybody rich. It seems unlikely to me that the same forces that might prevent AIs from being used to innovate housing will also prevent those AIs from being deployed to AI safety efforts.