Those changes are also reflected in the price of gold.
Make that deletion and I'm on board.
As for your next paragraph, if the price of gold goes up, then, in fact, everything else DOES become less valuable, at least as their value is expressed in gold units.
That's the very definition of the word "valuable".
All values have to be expressed in some unit other than the thing itself. You can't say that ten goats are worth ten goats. That statement fails to convey any information about the value of goats. But you CAN say that ten goats are worth one "talit" of gold. If some time later one talit of gold will buy 15 goats, then clearly goats are worth less in terms of gold. At the very same time, they might become worth MORE in terms of some other valuing index.
Almost anything can be used a a valuing index for anything else, but not all things are equally useful as a valuing index. The beauty of gold is that it is easily stored (hidden) and transported, does not deteriorate, is the same from place to place, etc... i.e. it has the characterisitcs of a good standard. There isn't anything holy about it, it's just useful and convenient. So. I'm afraid I can't concede the point. And I'm not being specious although I do appreciate the pun.
Yes, in terms of gold things would be less valuable.
But choosing gold as the reference is arbitrary.
You could just as easily choose crude oil.
“Value” is a human defined quantity. Ultimately value is based on a person’s time/labor.
If it takes 1 hour of labor to feed ones family for the day that labor and food “value” exchange has little if anything to do with the current value of gold.