Maybe I'm overlooking something here; if so, please let me know!
The Cloward-Piven strategy was to overwhelm the system with a massive amount of both protests (possibly violent) and also welfare recipients; this was supposed to cause a breakdown of both public discourse and also of public finance.
The idea was that the status quo in both politics and public programs would not be able to handle the new situation and would have to be replaced by something else.
According to Piven, the activism of the 1960s and 1970s was this strategy in action.
As I understand it, those are her claims -- and I completely agree with them so far. Her mistake is believing that the response of the system would be to give in to the demands of the activists and welfare applicants, and replace capitalism with democratic socialism.
Instead, in the 1980s and 1990s the system -- I hesitate to say "Silent Majority" -- responded by voting for right-wing Republicans and moderate Democrats, and by pushing for welfare reform.
The reasons why her strategy failed are that the number of producers must be greater than the number of parasites (or else the entire society collapses into chaos) and also that the producers tend to vote and otherwise participate in politics more than the average parasite. (There are other reasons as well, such as the fact that free-market capitalism allows upward mobility for those who are willing to work, so a temporarily-unemployed producer is on the side of the producers, rather than the parasites.)
As a hard-core political activist I'd like to encourage Ms Piven to agitate as much as possible, because I look forward to the results of her tactics. Bring it on, baby! As Lenin said, "The worse, the better."
As William F. Buckley, Jr., remarked, there may be a million violent rioters; there are a million and one lampposts.