I think you mean unions negotiate for relatively higher pay for people who have been with the company longer, or with more experience, but it would also negotiate higher pay for new hires relative to a non-union shop.
You're also thinking of manufacturing unions. I suspect a tech union would be a little different. Things like The Writer's Guild are also unions.
I'd certainly be willing to try it. I suspect pay would at least double. I mean right now you hear about high demand for tech people, but wages don't reflect that. Unions would help that problem. Unions would also prevent offshoring which drives down wages.