Well, what this article says is relevant for a small subset of "geeks" when ICQ (or AIM etc) was dying, but many people still used it and similar services, so a simple IM of this kind was still accepted as normal, thus XMPP as the alternative.

Normies (like me) were mostly on Skype or between ICQ (or AIM etc) and Skype. That is, that move to Skype was often spearheaded by "geeks", after it was mostly over the more conservative people were "geeks" too, as it always happens.

Frankly I'd say what hurt XMPP most was its adoption by various social networks being advertised as a selling point. Like "look, it's a universal protocol, Google has it, Facebook has it, even ICQ had an undocumented XMPP endpoint for some periods of time when they were playing with it, ... <I can add 2 Russian search and email providers and 1 social network to this list, and possibly plenty others> ...".

So when those big proprietary services just decided they don't want it, what's described in the article happened. Basically XMPP enthusiasts made their bed and had to sleep in it. Only it shouldn't have. Many "geeks" of that time were uncritically in awe of Google and Facebook etc, we seem to start forgetting this. People would defend dropping XMPP by them, would hope that these companies together would make some other universal protocol, make up all sorts of unbelievable bullshit to believe that all these companies are cool and big and making future.