jonnythan is 100% right that DLP RPTVs are going by the wayside. There is no logical way to argue this. You can use the argument that looking at what is in B&M stores does not count because none of us would buy A/V from there, but the fact is that there are not enough of us to keep a market sustainable. The much larger population of folks that do go to B&M stores and pay full price based on what they see in front of them or hear from the salesman define the majority of the market. Face it, we are the Niche buyers. Online is getting bigger and bigger but it does not hold a candle to B&M for purchases like TVs. What you see in B&M stores is the majority of the market. When a product falls out of those stores and into online only, it is because there is not enough sales to justify precious floor space (not counting those boutique manufacturers that don't really do retail sales). By definition, that product is no longer mainstream. And I don't think it has much to do with people being uneducated. It has to do with people not caring near as much about picture quality as to how the TV looks in the room. If you ignore any personal opinions on picture quality, it is hard to get around the fact that a 70" LCD mounted on the wall with thin or in-wall speakers looks better to many (including me), if not most, consumers than an 18" deep Mits DLP sitting in the room, whether it is in a nice cabinet or not.
That said, I have a Mitsubishi 82737 TV in my family room. Yes, I would have preferred an 80" panel hanging on the wall. When I purchased it, however, it was the largest TV screen you could get for a reasonable price. And the picture is phenomenal. While I can understand jonnythan's and others preferring the picture of a nice plasma or LCD, for me it was size over perfect picture quality. Although I have to say that I have a 50" Pioneer Kuro 1080p set and I think the two are very comparable. At nearly 4,000 hours, I am on the same lamp, although I purchased an extra lamp when I bought it, just in case.
In the end, I am not sure how anyone can avoid the fact that RPTV will not be here for long, without deluding them self. My guess is the only reason Mits is still in the market is because they are the only one in the market. If you have no competition and can undercut the price of panels, people like me, who want the biggest screen they can get with nice quality and are willing to have a big TV taking up living room space, will buy it. With the recent release of cheaper 70 and 80" LCD TVs from companies like Sharp, Mitsubishi will either get out of the market or be relegated to a smaller and smaller community of folks in that market niche. While I love my set, drool over the 92" and would hate to see RPTV die, I would be surprised to see Mits still making them in 2-3 years. I hope I am surprised. In my case, as much as I love my Mits, I would have thought long and hard about an 80" Sharp LCD instead, if they had them when I bought it. I have not seen one in person yet (2 weeks I see my Folks new set), but I am better the picture quality is good enough for me. When the videophile in me needs to come out, I switch to the projector anyhow. 82" screens are just too small. :P
As to my answer to the original question. I know why most people hate DLP RPTVs. Because they are not flat panels. Whatever their reasons, nearly everyone that sees my TV will agree that the picture is terrific but they have reasons that they would never have it in their living room. It's OK tho, I am fine with being in the minority. I was already there when I knew to come here to do the research before I bought it.