Agreed, I think relatively high compensation is something engineers can get caught up on when discussing the idea of unionizing (though its worth noting that we're paid salaries closer to electricians and plumbers than we are to specialist doctors, not that this is really apples to apples in terms of education required).

Even though we earn good wages, its relatively easy to see that workers are not often reaping the benefits of surplus value and have no ability to weigh in on determinations of how that value is allocated. More importantly, the advantages of a union are not limited to being able to negotiate a better salary, there are lots of workplace conditions that can be pretty oppressive in the tech industry, and unions offer the ability to improve all of them.