Tech salaries are too high for people to do that. At least in Europe. Having an union will fuck with peoples salaries.
It seems like there should be room for a happy medium somewhere where some workers in the US maybe don't get the same salaries but are also not having to spend so much on healthcare, get more time with their families, get better just protections, etc. Once you make enough money that you're not really worried about meeting your bills and can pretty much buy what you want the peace of mind is more important than the bragging rights you get over who has a bigger paycheck.
So I so 0 benefit for me to join a union.
But the answer is that your insurance shouldn’t be tied to your employer in the US. You don’t need unions for that.
In the Nordics quite many tech workers are in unions. For most people it's perhaps just about habits and solidarity, but they do offer tangible benefits like free consultation and legal representation in a case of dispute with your employer.
Unions are powerful because they can call for protests and employees who are in a union cant get laid off due to joining the protest. But its not worth if the job already has way better working conditions than like 80% of jobs out there.
Even without unions Europe wouldn't have US tech salary levels, those numbers come from other market dynamics.
Say all the engineers in all the top engeering companies by pay were suddenly in a union, how does the collective bargaining work on pay. You don't think pay would be lowered for high level engineers?
Collective bargaining would not apply to any of these salaries. Collective bargaining as we usually understand it sets the lower bound for salaries in a certain field, think of it as field specific minimum wage. Indeed, some Nordic countries have no minimum wage at all because ~all fields are covered by collective bargaining -- regardless whether the employees are part of the union or not!
So no, pay would not be lowered. I don't understand where this kind of a misconception comes from. Collective bargaining does not mean that everyone gets the same salary. As I said earlier, you are free to negotiate a higher salary, and companies wanting to attract top talent will still have to compete through compensation.
In the top engineering companies, collective bargaining could be used to negotiate other perks, like paid leaves, hour banks where you collect all work time exceeding a regular work day, paid parental leaves, and/or whatever topics are important for the work force. I'm not the one to define that though.
Collective salary bargaining is efficient in fields where the workforce is highly interchangeable, and the workers' ability to produce higher value is limited. If factory workers, miners, or nurses are not unionized they are really placing themselves in a precarious position.