> Specifically, if we had widespread “codetermination”, which gives board seats to union members, the people that build things would have a say in what they’re being asked to build.

We don't have legal or cultural barriers to leaving to work somewhere else if you don't like what your current employer chooses to spend their money on (and modern telecommuting counters issues from living in a one-employer town). Without those barriers needing to be compensated for, this sounds like just trying to seize control of other people's stuff.