Well, the problem with those 3 examples is I think they all basically do most of what people want from them already, so if they don't change that is mostly fine. Stability is more important for their users.
ChatGPT on the other hand, isn't finished baking yet, and all the companies that are building a product on top of it are doing it because they expect more, and they expect more on a VC startup timetable, which means quickly.
Edit: and, you know, given how new the space is, there is a relative dearth of companies who have integrated ChatGPT in mission-critical ways that can't withstand an API service disruption or two.
ChatGPT on the other hand, isn't finished baking yet, and all the companies that are building a product on top of it are doing it because they expect more, and they expect more on a VC startup timetable, which means quickly.
Edit: and, you know, given how new the space is, there is a relative dearth of companies who have integrated ChatGPT in mission-critical ways that can't withstand an API service disruption or two.