[ernst_klim]

> Is it because of something inherent to software development, or is it just that software development became a big job category in an environment that was skeptical of unions?

Unions are neither a good nor a bad thing. It's a price cartel, which is rent-seeking in its nature, but so are the employers. Thus effects of unions depend on competitiveness of the particular market. In low-paying markets they are clearly beneficial and counterbalance the monopsony.

Programmers exist in a competitive market tho. Average programmer has a great bargaining abilities and most people know it. If you are a senior you wont get much from union, it's just a hustle. If you are a junior/immigrant unions will harm you by raising the bar.

[banku_brougham]

>Labor Unions => Cartel => Rent seeking

You reached reductio ad absurdum in two tiny steps. So unions are seeking rent by virtue of legal ownership of the motion physical bodies, just as property owners seek rent by virtue of ownership of real estate.