The issue is, they hit pay-ceiling very quick, unless they go into management position. And really, who wants to be an IT manager? It's probably the second worst job in IT after IT project manager. chuckles
A 30 year old sr. software engineer will be paid not much less than a 40 year old one, even if 40 year old is much more talented, and deserves to get paid twice as much.
I suppose the same issue exists for pharmacists. Out of school, you're expected to make $110k; pretty much the same exact salary as RPh with 20 years of experience.
For example, if cool software engineer goes from $100k to $200k, then his boss, Mgr #1, is going to want like $300k, well, just because she's a boss. And, her director is then going to want $400k because people with power titles should make the most.
(Oh, and, by the way, everyone knows that Mgr #1 is probably the best programmer at the company, but she's 40 now, and her salary got too high, and therefore she would have had to move under R&D director PostDoc. But, he only allows PhDs with the title of 'principal' to work for him. So, now she has to be a mediocre manager.)
I really doubt a union would succeed unless you suddenly get a lot of programmers on board very quickly. Tech giants are big and if they chose to fight, they have a ton of cash to do it with.
Something is wrong that salaries never seem to rise with demand in Silicon Valley. We know there was a secret deal to help suppress wages at one point, but it's not obvious why it's been so successful. Is it new graduates, immigration abuse, internationalization, illegal price fixing?
A programmers union could probably force tech companies to double salaries. They all could afford to pay it.