[atemerev]

To clarify: initially, the first web browser evolved from a SGML-based documentation browser at CERN. This was the first vision of the web: well-structured content pages, connected via hyperlinks (the "hyper" part meaning that links could point beyond the current set of pages). So, something like a global library. Many people are still nostalgic to this past.

Surprisingly, the "hyperlinked documents" structure was universal enough to allow rudimentary interactive web applications like shops or reservation forms. The web became useful to commerce. At first, interactive functionality was achieved by what amounted to hacks: nav blocks repeated at every page, frames and iframes, synchronous form submissions. Of course, web participants pushed for more direct support for application building blocks, which included Javascript, client-side templates, and ultimately Shadow DOM and React.

XSLT is ultimately a client-side template language too (can be used at the server side just as well, of course). However, this is a template language for a previous era: non-interactive web of documents (and it excels at that). It has little use for the current era: web of interactive applications.

[eftpotrm]

What makes XSLT inherently unsuitable for an interactive application in your mind? All it does is transform one XML document into another; there's no earthly reason why you can't ornament that XML output in a way that supports interactive JS-driven features, or use XSLT to built fragments of dynamically created pages that get compiled into the final rendered artifact elsewhere.

[the_other]

My only use of XSLT (2000-2003) was to make interactive e-learning applications. I'd have used it in 2014 too, for an interactive "e-brochure", if I could have worked out a cross-browser solution for runtime transformation of XML fragments. (I suspect it was possible then but I couldn't work it out in the time I had for the job...)

If you can use it to generate HTML, you can use it to generate an interactive experience.

[cluckindan]

What if you used JS to make XSLT interactive? :-)