Laborers need a union because their work is not differentiated. Anyone can dig a ditch. Most people can put grocery carts away. With a little training, most people can even drive a bus. Because of this, market forces drive businesses to treat them inhumanely and pay them so little money that they can't support a family on it.
On the other hand, engineers are highly differentiated. I'm a DevOps engineer. I'm probably one of the most highly paid engineers in my company.
I can assure you, the market is not something that I'm afraid of. Engineers do not need a union. If they get good at their jobs, they are highly differentiated.
I'd go further and say that unions would be detrimental. I remember my sister working at a grocery store and having to pay union dues cut and it would cut into her paycheck. A necessary evil perhaps for that field, but in ours would be overhead and cost that didn't need to be there. It would probably just make me poorer.
Ditch diggers may need a union, but if the ditch is dug with a manual shovel they won't get one because as soon as they organize the boss will fire them and hire someone else. A ditch digger who operates a backhoe needs a union and can get one because you can't hire just anyone to operate a backhoe (I can operate one, but I'll spend the first several days randomly pulling levers until what I want happens does - don't put me close to something important for the first week as I'll destroy it moving the wrong way - after a month I'd be good, but that is a month of paying me while not getting your ditches dug)
Grocery workers rarely have a union, and when they do they rarely go on strike because the workers don't really have enough skills to not be replaced. It only works at all because every clerk going on strike at once is hard to replace.
On the other hand, engineers are highly differentiated. I'm a DevOps engineer. I'm probably one of the most highly paid engineers in my company.
I can assure you, the market is not something that I'm afraid of. Engineers do not need a union. If they get good at their jobs, they are highly differentiated.
I'd go further and say that unions would be detrimental. I remember my sister working at a grocery store and having to pay union dues cut and it would cut into her paycheck. A necessary evil perhaps for that field, but in ours would be overhead and cost that didn't need to be there. It would probably just make me poorer.