If riders who start overperforming their contract should immediately receive salary increases while underperformers don't receive decreases, then every single team will, on aggregate, be overpaying their riders. That isn't sustainable at all.
Have not said they should increase immediately.
But if they want to continue working with them, it is probably a good idea to be proactive about it and keep everybody happy/motivated to continue working with each other. Saying "no, you have contract. Stop complaining" is probably not they way to deal with a person. Especially one who has shown above average talent and performed well. You risk losing them to a team or someone who can offer them more. Rider might still want to stay at his current team, if they can reach an agreement, or he will try to leave if they cannot. Especially if there is a fallout between manager and employee. Happens at every company. Not just in sport.
We are only talking about a single rider or a rider who has made better results than the average cyclist.
This isnt a general discussion. Never have I said, at least, that there should be automatic increases for a rider who performs well. An underachiever who doesnt live up to their paygrade, will probably have to lower their demands. The employer usually has to first support or help them if they are underachieving. They have to investigate and make up a plan together. They have different responsibility towards the individual in these matters. There are laws about this sort of stuff. If they are sick or injured, you usually get paid less anyway. Thats just how that works.
Teams can seek to terminate contracts with riders as well, if they have grounds (bad behavior, not showing up or other reasons you can think of), or reach a settlement of some kind. It goes both ways you know.
As far as I know, Van Gils is just seeking ways to terminate it and looking at his options. Nothing wrong with that, if he doenst want to be at the team and isnt happy about it. Maybe he was happy 8 months ago, but things change. Thats just life. He now knows he is worth way more, but the team doesnt see it that way or cant/wont change the terms. They have a disagreement. It happens.
He ends up staying he will just have to deal with it, but likely the team doesnt want that for morale in the team and will come to an agreement in the end if they cant move past it going into next season. Usually what happens when people cant agree with each other.