There is a big difference between being an addon developer running in to the limitations of an API, and the entire product stability getting so poor that it risks the failure of the business. I don't think it's fair to use the same "development hell" term for both of those.
I would rather nobody did make another platform behavior. This kind of feature duplication causes a bunch of other problems too. Again, we saw much of what happened when people tried hacking around with the official engine code in C2: broken projects, incompatible changes, no good way to switch between them, the official addons ending up superseding them but people being stuck with old buggy third-party versions of addons, confused users who don't know which they're "meant" to use... some of which takes years to play out, and leaves us having the support headaches of trying to help people with things like broken projects long after the third-party developer responsible has left the community. As I was saying previously, the consequences end up with us and our team, and as a small company with limited resources it is especially painful.
Of course, it is possible to make a comprehensive and well-supported public API. It just takes time. We routinely get far, far more requests than we could possibly act on, and things like developing a large API that we promise to support indefinitely is potentially a major project and a major long-term maintenance burden, and we have to balance that with literally hundreds of other things. If I could click my fingers and have it all done, of course I would, that would be great! Unfortunately we have to deal with the real world and limited resources.