You think progressives in IN put him over the top there? Really? I think he won IN because lots of people (including a few progressives) wanted to give change a chance and lots of new voters were enthusiastic about him.
Sure, many of those people stayed home in 2010, but that's always the pattern - fewer people turn out in off-year elections, and the President usually loses seats. I've seen little that indicates the pattern was generally different because Obama was there.
I didn't find the article you posted persuasive. Or I think it only describes a small number of people. Carville versus Kucinich or something. E.g. "The Left has been especially critical of President Obama over the last three years." Really? http://www.gallup.co...remains-high.aspx Or is this a "no true Scotsman" argument?
If you want the system to change, you have to work within it. That means supporting the better candidate(s). They're not all the same.
FWIW.
Cheers,
Scott.