I agree, but this is something else. The parent was talking about evolving schema. You're talking about what is effectively unstructured data. In this case, the main concern is being able to store the data first, and figuring out how to deal with it later, at the application layer, after you've added intelligence to deal with the new schema(s).
Otherwise you could create a table for every XML schema you would have and store it like that
Some systems require that. It's a new schema every week/month. And this is not the development of the system, this is the bread and butter of it.