The USD to gold exchange guarantee ended in the early 70s, long after the great depression. And there have been many economic meltdowns since then. The two are not related.

When the economy is backed by something real, credit generally keeps up with the broader economy. It can't expand beyond reserves of real resources. Now that the money is not backed by anything, credit can expand infinitely. Credit generates most of the inflation which is a direct and ever increasing tax on the poor. It has been going on for half a century and shows no sign of stopping. The best part is even the mere attempt to stop it will cause a meltdown since the economy is addicted to credit.

We had metal standards way after the great depression, till 1971. Bretton Woods system made USD an international reserve currency, but its convertibility to gold was guaranteed. In 1971 US gov decided to not guarantee that anymore, because it gave a ridiculous advantage to US. Germany was rhe first county to left Bretton Woods, France sent a battleship to collect gold in exchange for US dollar reserves etc.. and the system collapsed. It's called Nixon shock I think.

So, leaving the international system helped the European economies greatly then. It makes sense some other countries are having the same idea now.

We had currencies backed by gold for hundreds of years before the great depression without anything equivalent happening. The great depression happened soon after US momentary creation was handed over to the private Federal Reserve.