Radical theorists never really go away. The debates over what Machiavelli really had in mind still continue, but they are almost irrelevant because it is not what he meant that matters, but what The Prince has meant to actual leaders and rulers as a guide for taking and holding power. The scribblings of every halfway notable leftist scribe drawing out a theoretical society built on some perfect method are still around, no matter how much they have been discredited in practice.
Alinsky is the last of them, not the truly last one, but the last of them with anything meaningful to say about applying leftist politics to the modern state, far less interested in how an ideal system should work and far more interested in how to realistically seize power in a modern state with open elections and all the other aspects of a free society.