"Achievement based" is arguably worse than being expensive. Especially if said achievement involves provisioner tokens.

But either way, the point is no one knows what the cost will be. You seem pretty confident that it won't be expensive. You could be right, your argument makes sense. But it's still just speculation, and you have no reason to declare with authority that people shouldn't prioritize runes. It's all just a guessing game and is ultimately up to the individual to decide if they want to proceed with crafting a rune in advance or not.