Good question. I bet "other" is more likely, just because of the delays that the R-972 has suffered through.
Definitely seems true. The construction industry has its own challenges, but nothing quite as dramatic as the consumer electronics industry.
Consumer expectations, probably worsened by some weaknesses in consumer education. Too many people shop by feature list, and deviating radically from the traditional feature lists is a risky gamble. Look at reviews for the BDP-83 and see how many comment on the lack of Netflix or other streaming support - all of which relate to the absence of heavily-compressed feeds from the feature set of an HD video disc player. For surround processors, it's likely compounded by economic factors. For example, a standalone room correction unit would need to have good enough ADC/DAC hardware to be sonically transparent, and it would need to be paired with separates - it couldn't be used with a standard receiver. That makes for a limited market, and one that will be more demanding of that ADC/DAC hardware. Plus it would need the same sort of processing resources that a surround receiver or processor needs, so you are buying a pretty substantial DSP chip twice. You also may need to provide a video output so you have a convenient setup OSD. And don't forget a remote so you can set it up from the couch and make setup changes on the fly. All of a sudden, you've duplicated 80% or more of the hardware you'd need for a surround processor.

What about separating audio and video processing? It's a good idea, and if the industry had gone with IEEE-1394 (FireWire) for audio and DVI for video it would have been fairly practical. With HDMI, though, the two signal paths are trapped inside a single cable. That makes it more complex to separate the two. It can be done, but you basically have to run everything through the audio processor and then pass video on to a separate video processor. Not easy to do - it ends up being cheaper to do it all in a single chassis. In some ways, you could argue that HDMI is a big reason for surround processors starting to do everything. Another reason to be frustrated with HDMI...

There are instances where "do-everything" can be reasonably scaled back. I would rather see a media client/server stay separate from a surround processor, for example. Sure, the hardware may be robust enough that it's capable of acting as a media client for a server of some sort (DLNA perhaps) or even streaming services like Netflix, Hulu, or YouTube. That doesn't mean it's a good idea, though.