To make the above situation even trickier, let's say the homeowners had a landline for years, but just recently switched to a VoIP gateway. Their VoIP gateway operator advertised a feature that their outgoing caller ID will make it look like they're calling from their old number. This is a real and desirable feature for lots of people. I'd rather not have police disregard all calls from VoIP gateways.
But to GP's point, of course what we really need is a genuine verifiable caller ID. Or at least some sort of verification that's instantly available to 911 operators. In this case, the VoIP provider should be able to assert that the call really is coming from that address in a way no one else can spoof.
Similar with prepaid credit cards if memory serves.
Flipside would be: don't use a burner phone/SIM to call 911 - or at least have an alternative method of verifying location / address.
And can't law enforcement map that to a physical address within a light speed equivalent amount of time?
Unless a swatter is "the phone call came from inside the house"-ing, it should have been easy to filter out for maybe, conservatively, the last two decades.