It's not about a "gotcha."
Browsers once supported the GOPHER protocol but dropped it around a decade ago. This serves as an analogy: if users don't use XSLT/XML daily, browsers may eventually drop support for XSLT - supporting features cost money
That's not a great analogy. Firefox once supported RSS feeds as live bookmarks and dropped it, and not because people didn't use it, because people did use it and bemoaned its loss for years afterwards.
This is a "cope" argument. GP doesn't mean literally no one uses it; they mean very few people use it. Yes, there are people using RSS/XML, but that proportion is (will be?) 0% when rounded to the nearest Nth decimal. They are, unfortunately, insignificant.
