121.5 MHz ELTs just send out a 'blind' signal for SAR to home in on.
The new 406 MHz ELTs typically send a GPS location to the satellites.
A transponder sends out a four (4) digit signal, controlled by the pilot, which the ATC control radar recieves.
Flying is a risk. If the government or volunteers can help me out when things go south, then great. But I'm out there knowing I control my destiny not ATC or SAR.
ATC charter is to seperate airplanes. Rescue support is on the list but it's not there main focus. Fortunately they don't get a lot of practice. I can't speak for them, or the SAR folks, but I can easily imagine how quickly things can get complicated. So many entities involved, working realtime...geez.
Again, the people working ATC are awesome. Period.