I don't see unions ever becoming necessary for hackers. Such organization might become for someone with highly-specialized, non-transferrable skills, such as operating Ford auto plant equipment, or engineering Amtrak trains. If you've devoted your career and livelihood to a single company, the thinking is that that company has certain responsibilities to care for you (whether this is indeed the case is an argument for another day).

Quality programmers, on the other hand, are highly mobile, highly sought-after, and can quickly and easily upgrade and alter their skillset. They aren't married to a single company, or even a single industry.

I think unions can be can't be considered even marginally feasible unless available labor supply outstrips demand. In this case, the situation is reversed, and I can't imagine what benefit unionization could possibly bring to the programming industry.