Of course, any workplace union is free to negotiate the terms for how its workers are compensated on its own. Connecting salary to length of employment is just

Of course, any workplace union is free to negotiate the terms for how its workers are compensated on its own. Connecting salary to length of employment is just one way. A hypothetical new software-themed union could define another scheme for a pay scale. (And as a side note, for my part, I would rather my salary be defined as simply as "as much as I can get" rather than my skill or my tenure.)