I do undesrstand your point and I appreciate that I went a little far but...I do shop at Best Buy and such. I also know that many of the sets for sale at such stores are often not the current models (especially at the end of the year). The retailers do not bring in the newest models until they have eliminated their inventory, or until they are being produced in sufficient quantity or at an acceptable cost. If you look at upcomoing sets from most manufacturers you will see 720p disappearing using retail stores as a guide is faulty.
When looking at technology you have to be ahead of the cureve. 720p is the most popular, certainly, and I think 1080i is technically the standard, though plenty of HDTV is braodcast in 720p. 1080p isn't much more than 1080i, none of which requires 720p.
720p is popular and common, but it's on the way out. These are essentially starter TV's, for the non-videophiles.