> JavaScript is better than XSLT in every way
Obviously not in every way. XSLT is declarative and builds pretty naturally off of HTML for someone who doesn't know any programming languages. It gives a very low-effort but fairly high power (especially considering its neglect) on-ramp to templated web pages with no build steps or special server software (e.g. PHP, Ruby) that you need to maintain. It's an extremely natural fit if you want to add new custom HTML elements. You link a template just like you link a CSS file to reuse styles. Obvious.
The equivalent Javascript functionality's documentation[0] starts going on about classes and callbacks and shadow DOM, which is by contrast not at all approachable for someone who just wants to make a web page. Obviously Javascript is necessary if you want to make a web application, but those are incredibly rare, and it's expected that you'll need a programmer if you need to make an application.
Part of the death of the open web is that the companies that control the web's direction don't care about empowering individuals to do simple things in a simple way without their involvement. Since there's no simple, open way to make your own page that people can subscribe to (RSS support having been removed from browsers instead of expanded upon for e.g. a live home page), everyone needs to be on e.g. Facebook.
It's the same with how they make it a pain to just copy your music onto your phone or backup your photos off of it, but instead you can pay them monthly for streaming and cloud storage.
[0] https://developer.mozilla.org/en-US/docs/Web/API/Web_compone...