The problem with common APIs is that they are a lowest common denominator. I deal with this all the time with Microsoft's Bot Framework - which is somewhat shitty open protocol for writing chat bots that plug into a whole range of messaging platforms, including Teams and Slack. It's functional, more or less, but it by necessity has to target the lowest common set of capabilities of the services it plugs into, and that makes it clunky as hell. And you still end up having to write a bunch of bodgy platform-specific code to get it to do anything interesting.
Yes but at least you are allowed to write that bodgy code. In some people's ideal world such APIs would be hidden behind DRM, chatbots only physically possible with godzilla's permission.