The most interesting part of this, to me, is it represents the economy figuring out what is true. The English monarch is pretending that the exchange rate is yea much gold to a noble. In reality, it is not. The economy detects this and tries to work around the lie.

In my opinion the sensible way to fight this is to stop pretending - if there is no way to stop counterfeiting, then pretending that the rate is a fixed value should have been abandoned. Let people use their own weights, measures and systems of credit. Of course, that might have inconvenienced the king in whatever wars he wanted to wage so probably not a practical option (from his perspective). But better for the rest of us.