It would probably help to be clearer by what we mean by incremental. The height of the tallest man-made structure is jumpy, but the jumps seem to usually be around 10% of existing height, except the last one, which is about 60% taller than its predecessor of 7 years earlier. I think of these as pretty much incremental, but I take it you do not?

At least in the AI case, when we talk about discontinuous progress, I think people are imagining something getting more than 100 times better on some relevant metric over a short period, but I could be wrong about this. For instance, going from not valuable at all, to at least more useful than a human, and perhaps more useful than a large number of humans.