i remember during the financial crisis thinking if only the tea party and the occupy crowd realized they were two sides to the same coin maybe something great could have happened. I feel like that dawned on the powers-that-be and the old divide and conquer technique was quickly applied; tea party turned far right, occupy turned far left and they've been fighting ever sense.
It's eerily similar to the Machiavellian approach to alliances. Something along the lines of joining forces only with those who are weaker than you but can be used to amass power against your greatest threats. In the context of the examples you provided: major party identifies small group making noise, major party aligns themselves with that group, major party exploits that group as tool against opposing major party, major party under no obligation to truly pursue agenda of absorbed group due to relative power.
