In a way, that's what Google is doing. Trying to decouple phone numbers from devices. And, IIRC, the underlying product they based it upon (Grand Central) does that via SIP -- the backhaul isn't another group of phone numbers, but IP addresses on devices that provide a presence to the server.
caller -> phone number -> SIP server -> SIP user account -> zero or more presence entries for that account -> SIP over IP -> SIP device -> callee
With the possibility of many SIP devices connecting to the user account on that SIP server.
The problem is: there aren't enough SIP devices out there to make that currently more than a niche environment. To reach a huge audience, you need to allow legacy devices in too. And they don't use SIP, nor a SIP-like mechanism, to address themselves and provide presence information. They use ... phone numbers.
Hopefully Google didn't remove SIP from Grand Central when they bought/re-branded it. SIP, or a SIP-like protocol, is really what the future of telephony you're hinting at, ought to be. But we're not there yet. Carriers block it, refuse to subsidize devices that include SIP clients, etc.
LTE and WiMAX (which layer everything on top of IP anyway, making something SIP-like inevitable) will hopefully change that... but we'll just have to wait and see. Hopefully, though, SIP wont go the way of multi-cast-backbone, and end up getting replaced by lesser & proprietary "streaming protocols" put in place by companies that had no interest in doing things the right way, nor in adopting something done "the internet way".
no subject
caller
-> phone number
-> SIP server
-> SIP user account
-> zero or more presence entries for that account
-> SIP over IP
-> SIP device
-> callee
With the possibility of many SIP devices connecting to the user account on that SIP server.
The problem is: there aren't enough SIP devices out there to make that currently more than a niche environment. To reach a huge audience, you need to allow legacy devices in too. And they don't use SIP, nor a SIP-like mechanism, to address themselves and provide presence information. They use ... phone numbers.
Hopefully Google didn't remove SIP from Grand Central when they bought/re-branded it. SIP, or a SIP-like protocol, is really what the future of telephony you're hinting at, ought to be. But we're not there yet. Carriers block it, refuse to subsidize devices that include SIP clients, etc.
LTE and WiMAX (which layer everything on top of IP anyway, making something SIP-like inevitable) will hopefully change that... but we'll just have to wait and see. Hopefully, though, SIP wont go the way of multi-cast-backbone, and end up getting replaced by lesser & proprietary "streaming protocols" put in place by companies that had no interest in doing things the right way, nor in adopting something done "the internet way".