Do you really expect people to pay $830 for a 24 station analog card along with the computer and other crap they'll need to run Asterisk?
Do you really expect the future of telephony ends with PSTN?
Asterisk quite happily talks to my home phone handset (which talks DECT on one side and SIP on the other) and my VoIP provider that I already had. I'm running it in the ample spare capacity on my Atom-based home server that I already had (which is my router, MythTV backend, web server, database server, NAS, ...).
I paid nothing to run Asterisk, and it's not a stretch to imagine home phones in a few years having enough compute capacity to run a two-channel Asterisk install without any drama.