The problem is that we don't expect one. The problem goes largely ignored. Even setting aside the movement to dub the whole thing a hoax, it's hard to make real progress among those who accept that progress needs to be made.
Dealing with climate change comes with costs, at least in the short term. Everybody would like to pay as little as possible. That will be more expensive in the long run, but today it seems worth arguing about. There are many options and it's unclear even which ones are effective, so we dither.
That's exacerbated by the United States, where climate change conspiracy theories are a significant factor in one of the biggest CO2 producers. As hard as it is to act, it's even harder with the US opting out of paying any of the costs.
A "Pearl Harbor moment" could change that. But there's none in the offing.
Not every situation has a "Pearl Harbor moment". Most situations don't so why should/would we expect one?