Not suggesting an alternative model here, but I think that Google et. al (based on my own time working on Chrome) don't take that responsibility quite as seriously as they should. Being responsible may be an accident, but being dominant in any given area is not. The forces inside Google which take over parts of the world do so without really caring about the long term commitment.
It is so possible to preserve XSLT and other web features e.g. by wrapping them in built-in (potentially even standardized) polyfills, but that kind of work isn't incentivized over new features and big flashy refactors.
It is so possible to preserve XSLT and other web features e.g. by wrapping them in built-in (potentially even standardized) polyfills, but that kind of work isn't incentivized over new features and big flashy refactors.