Average Joe sees HD tech still too pricey and postpones purchases until prices begin to come down. Average Joe doesn't care how good something is if it costs too much. That's the bottom line. Another fact is that Average Joe will be buying a HD-capable television first, and given that those are pricey too, most will only buy the TV for now.
And many are even waiting for the "full" HDTV feature even though the "HDTV-lite" would be just fine. They just know that there will be a full version soon enough, so they're not so keen in jumping to the lite-wagon.
That's how it is, sadly. Average Joe is informed about two different formats and because the devices are expensive, those two are very good reasons for him to not buy right now.
(Sadly, Average Joe has no problem buying a crappy 50-dollar SD-DVD player only to find out that it breaks soon after warranty has run out, and then buy another one. And another one. People just can't recognize quality anymore... Almighty price is everything today.)