Individual employees are free to negotiate individually beyond that. Many do just that, but of course it’s less likely to succeed since individuals don’t have the ability to threaten industrial action.
That's the deal you made when you joined a union. If you did not understand that deal, then I'm not sure what to say. Being in a union isn't some automatic path to employment nirvana or something...
In fact, there could even be a doorway to a lawsuit against the employer for treating a specific employee differently than all the other unionized employees. Unions make things... difficult, despite whatever nostalgic views some may carry towards them.
Employers are already not giving anything for free to employees. They do it when forced, either by market forces or the threat of organised workers.
Maybe you should work for better companies?
This is not how unions operate in reality. But regardless, you either get something because your employer thinks it will make your happier, or you get something because your union insists on it.
Why would you get special treatment just because you're in a union? Your union has to negotiate and accept things on your behalf... not you. You lost that right when you joined the union.
It's inescapable and unavoidable for any sufficiently long-lived bureaucracy. By the time you have full-time, professional union employees running things, the disconnect between what actual workers need/want grows uncontrollably.
The entire point of being in a union is for collective bargaining power. What incentive would an employer have to bargain with individuals directly, only to then get raked over the coals by the union for everyone else too?
Treating you special is a liability for the employer when dealing with unions.
When you joined a union you stopped being an individual and you became part of the collective union. That's what you signed up for... and these are the consequences of that decision.
It is absolutely true in every union contract I have negotiated.
That is typically false. You are bound by the collective bargaining agreement.
It's entirely up to the parties bargaining how much discretion the employer has to adjust terms during the life of a collective bargaining agreement.
For pay specifically, it's not uncommon for the union to propose wage floors and allow some individualized bargaining. It's also not uncommon to specify a full wage schedule for the sake of transparency.
The workers get to decide what makes sense for them. Sometimes they decide on different systems for different career tracks.