you can say something like that only with a power of hindsight, knowing what was a useless fad and what was a ReVolUtioNary TecHnOLOgY

If you think of XML (and JSON, YAML) as a standardized CSV that can handle hierarchy I think that's beyond a useless fad. There are lots of edge cases in parsing data and having standardized tools for that makes it a lot easier for systems to communicate with each other.

I think the hype was there because companies needed to update their data to follow standards and update how that data interacts with other companies. The specifics of XML are less relevant - once things are standardized there can be standardized ways of converting to other formats.

Imagine needing to write custom parsers for every API; not needing that enabled SaaS APIs to be much more practical.

The point is that media hype predicted 500 of the last 2 technological revolutions... and only missed 1 or 2.

(And well, the OP's example of the internet is one that they missed.)