>> It wasn't always like this. 15 years ago, when ICQ was huge, everything with a screen, keyboard, a network interface, and a way to run arbitrary code had an unofficial ICQ client for it. Most people haven't ever seen the official clients. That's just one example. What happened?

Crony capitalism and big tech monopoly is what happened. These companies achieved success by doing innovations once but today they no longer want to work the hard route of innovating things. Instead, they're using the "legal" and convoluted route that involves closing the source code or build processes of everything, acquiring the small competitor who tries innovation and shut it down, encouraging walled gardens and non-standard APIs everywhere, etc.