I agree with much of your assessment of the Dems but not so much with their motivation. Sure they make excuses for their losses but then that is politics. Why is it that the Dems seem unable or unwilling to form a solid block like the Repubs do to them? Why did Obama spend the first two years of his first term rehabilitating the Repubs in the name of some supposed bipartisanship ( the Repubs weren't actually interested in reciprocating ) so much so that the Repubs went from the pits after GW Bush/Cheney to gaining control yet again by Obama's second term whereby they stymied everything he supposedly tried to do!
How can any intelligent person believe in this stuff or accord them the respect a real opposition party would be due? The Dems seem to be the old guard cronies of the Repubs with the ordinary citizen and working person the losers. The Dems are both the safety valve for the elites and also serve as a stop gap in case the working class attempts to participate in this democracy.
Where we differ is that I believe that the Dems are the set in stone old guard who have arranged themselves so as to get enough campaign donations from the corporate elites sufficient to retain their seats election after election just as long as they do not really interfere with Republican legislation. The Dems say they protect Medicare and Soc Sec but to be honest ...I don't feel safe with them protecting those programs.
Is it really so well orchestrated that democracy is dying in America because the Dems appear to drain away strength rather than encourage it. Look at what they did to Bernie.
We need term limits in Congress is what because it is my belief that the majority of Dems do not really want to beat the Republicans at most things. The Dems just want always lose narrowly allowing the Repubs far more influence than is healthy for our country.
The Dems took Bernie away from us and ended up putting Trump in the WH. That is our Dems!