I use OTA HD for all my HD DVR's at home since I live in an area not served yet by dish HD lil and the problem is not just putting a converter box before your coax input vcr or tv. The real problem is the antenna. I've picked up a OTA signal before with a coat hanger and alot of people watch OTA probably have poor or even regular antenna's which worked with NTSC. Finding the right antenna for your ATSC signal can be a real problem even if you got to the web site to look up which type you need. Not the first antenna you buy will work. You really need a voucher for new antenna alot of the time. Alot of people will fall off the digital cliff rather than not have a converter box.
Not wishing to beat a dead horse, but there is no such thing as an ATSC or HDTV antenna, despite the hype you see on antenna packages. That being said, there is a strong possibility that people who have gotten a usable picture on an analog TV with an existing antenna will not get one at all with a digital signal on the same TV with a converter box, or for that matter, with a new digital TV.
(By the way, all TV's 13" and up currently on the market have ATSC tuners.) These people are left with two options: get a satisfactory antenna or subscribe to a pay TV service.
Tell all this to an elderly widow (or to anyone not technically inclined), to whom a TV remote is a "clicker" and is totally at a loss when it comes to the antenna mystique.
Although Thomas Jefferson said, "Delay is preferable to error", in this case, delaying the changeover is an error, despite the good intentions of the president, congress and Consumers Union in promoting the delay.