https://www.sagaftra.org/production-center/contract/810/rate...
Daily rates for developers, dbas, qa's and such...
The same guild could make special rate sheets for different stages of a firm. For example SAG has a daily rate sheet for indy films, a software dev guild could have one for startups as well. This could at least prevent abusive startups.
https://www.sagindie.org/signatory/
If you are a star developer equivalent to a celebrity actor, these would just be the minimum rates. There is nothing preventing a studio from paying more.
If anything this would resolve the use of contract labor 1099 misclassifications. If you are good enough to get paid above 120k you could have a loan out corporation and deduct more of your costs while still paying union fees.
https://abspayroll.com/loan-out-companies/
https://firemark.com/2015/01/12/should-you-have-a-loan-out-c...
This wouldn't be a an factory type union. It would be something like a professional union like SAG.
Read the rate sheets to get a better understanding.