What about outside of promotions? I’m not going to get promoted every year and I certainly don’t want to only be able to get a sizable increase tied with promotions.

Although I do agree they are not fundamentally incompatible. You can have a large number of hands within a job level and have the ability to jump bands for example. But then this somewhat goes against the typical union (at least in the US) thinking where there is typically a step progression “up”.

Fundamentally, at least in terms of compensation, this seems to be about how we view money in general rather than specifics of unions. Ie should everyone be paid more or less the same for the same job or should there be wildly different compensation. For unions I typically see salaries clustered, that every senior engineer for example does more or less the same job. Currently in tech the view isn’t that. It’s more the one senior engineer can dramatically out perform another and should be compensated accordingly.

If a senior engineer can outperform another dramatically, he will get promoted to principal sooner than the other and is probably getting higher bonuses, even if their base wage is currently the same.

If a "10x" senior engineer moves to another company he will probably seek a job as principal engineer and get a higher base wage than older employees that have less technical aptitude than him.

Negotiated salary bands do not go against meritocracy.