Admittedly, I don't know that much about the contracts between CC providers and merchants, but in the big picture of things, CC providers are the giants and Valve is the little guy, so I'm pretty sure Valve doesn't have a lot of leverage in those negotiations. Otherwise, presumably the CC provider would be unable to initiate the chargeback in the first place. The fact that the chargeback itself is successful (Valve's retaliation notwithstanding) is evidence that the contract between CC provider and Valve allows chargebacks.
In this particular case, what this probably means is that CC providers need to include a "no retaliation" clause in their contracts for customers who issue legitimate chargebacks. That's assuming CC providers care, and maybe they don't, but point is they have the power to fix this and if it becomes a problem for their customers presumably they will.
But I don't think any of this solves the broader issue though. In general I don't think you can depend on having a powerful authority like a CC provider side with you like this.
[1] https://www.youtube.com/watch?v=urS8GmwmeWQ
[2] https://motherboard.vice.com/en_us/article/8qwvz5/how-cherry...
The real problem is that a Steam "purchase" are fundamentally an undefined-term rental. When you "buy" a gsame, you are buying nothing, and then Steam might let you access a game if they wants you to.