Here's why XML will endure for the next 100 years

Michael Kay:

Standards like XML survive for centuries because the cost of change is higher than the benefit. XML might be displaced in particular areas, but there needs to be a very strong incentive to change in an area where the cost of breaking compatibility is not too high. That's a high hurdle to get over.

Norman Gray:

I'd guess that lots of people have favorite ways that the XML syntax is annoying, but it's a very 'engineer's' solution, which isn't pretty, but which is stable because it's being pulled in so many different directions at once. I suspect large chunks of the various constraints would have to change, before the solution space would change enough to make a radically different syntax something other than a minority taste.