Actually… Mobile providers have been screaming at manufacturers for years about this. Google were the first to implement an answer. Go lookup Advanced Mobile Location.

Supported by Apple and Android for some time now. (Google since 2010 and Apple shamefully since 2018). And it’s a simple enough standard… You dial 999 (or local emergency code in the country you’re in), phone turns on WiFi/location services and either texts or HTTP posts the location to an endpoint.

It’s not globally ubiquitous, I’ll grant you that, but that’s a function of telecoms networks… And it will propagate sooner or later.