Missing Climbers Solution?

Wouldn’t it just make sense to those who enjoy mountain climbing to just carry a simple GPS device that could transmit your location when you’re embarking on difficult trips? I mean, why there isn’t some kind of universal device that could globally transmit your location to a search and rescue unit is beyond me. Make the device something you could buy in an REI type store and it’s registered to a global database. You only turn it on before you leave and that way the system knows when you turned it on and if you’re hitting your emergency button. I mean, isn’t this technology available today?