You have no idea. New projects with XML-based formats and interfaces are being implemented all the time. XML isn’t going anywhere.

There was fresh COBOL code written up until early 1990s too, long past its heyday.

Thing is you couldn't swing a dead cat in 00s without hitting XML. Nearly every job opening had XML listed in requirements. But since mid-2010s you can live your entire career without the need to work on anything XML-related.

Apple’s operating systems to this day make heavy use of XML by way of plists. You can’t have an app without it.

https://en.wikipedia.org/wiki/Property_list

I guess? Although in the few iOS/watchOS apps I made I never edited it manually.

But it’s still there and needs to be supported by the OS and tooling. Wether you edit it manually isn’t relevant (and as counterpoint, I do it all the time, for both apps and launchd agents).

Of course it's there. Expecting all the stuff laid in 00s disappear overnight would be unrealistic.

COBOL code is also still there.