Wired has kind of a crazy article about how the gov is ready to subsidize - to the tune of $1bn - a switch to digital TV. It quotes lots and lots of talking heads, most of whom seem to be extrapolating growth rates based on now.
I'll just point out that that's silly; since this is a classic network market, growth rates will become increasingly exponential as more people make the switch. Of course, people won't make the switch until they've got a reason - switching costs are massively high, so a killer app (show, etc) is necessary.
But ultimately, remember, this issue is about the Replication Wars - it's in Hollywood's best interest for the gov't to subsidize this, given the Broadcast Flag.