I think that's all pretty accurate and nothing in the explanations as to why it's happening strikes me as wrong or overstated. But one response in the link above that I want to highlight is from David Frum, a Bush administration official who presumably has a decent handle on the workings of the party and it's supporters:
Human beings will typically fight much more ferociously to keep what they possess than to gain something new. And the constituencies that vote Republican happen to possess the most and thus to be exposed to the worst risks of loss.
The Republican voting base includes not only the wealthy with the most to fear from tax increases, but also the elderly and the rural, the two constituencies that benefit the most from federal spending and thus have the most to lose from spending cuts.
All those constituencies together fear that almost any conceivable change will be change for the worse from their point of view: higher taxes, less Medicare, or possibly both. Any attempt to do more for other constituencies -- the unemployed, the young -- represents an extra, urgent threat to them.
That sense of threat radicalizes voters and donors -- and has built a huge reservoir of votes and money for politicians and activists who speak as radically as the donors and voters feel.
Much of the discussion about Republican obstruction revolves around it's party actors; people like Newt Gingrich, John Boehner, and Grover Norquist. But Frum is suggesting something I think is an important factor in this, which is that the obstruction is what Republican voters want. We've seen that the few Republicans that have tried to work with Democrats are facing primary challenges from voters and a person they see as more in line with Republican dogma. And part of that dogma is to oppose everything Democrats support. I can't remember his name, but the guy who just won one of those primaries even said that bipartisanship should mean Democrats changing their views to agree with Republicans. That's what the voters want.
I could be talked into a theory that says Republican leaders are helping fuel voter radicalization. Surely at least part of voter preference is driven by elites within the party. But it's really hard to flesh out the causal links and determine where this stuff originates from. I know at least some in the poli sci field are trying to do that. And maybe they have in the time since I've been in school.
Until I see the findings, I'll just say that if voters aren't already there, and the party elites are really the ones driving them to radical places and convincing them that obstruction is a good idea; those party elites are doing a hell of a job and we should look into how they are doing it because it poses some important questions for the idea of a representative democracy where politicians are supposed to be responsive to the people, and less so the people responsive to the politicians.