This is a real danger. There are several ways to counter it. One is to make as much production technology as we can open source and ensure it is well spread. This is what the RepRap and Open Source Ecology projects are doing, and the progress has been tremendous over the past years. Publishing everything counters patent threats, GPL-like licenses prevent exploitation without contribution, self-replicating machines make the technologies both cheap and available. This is my favorite way of countering the threat.

Other methods include government intervention, revolution of the (ex-)workers, consumer boycotts (off the grid communities) and benevolent corporates. None of them are as effective, and very few of them can be worked on in the short term.