There's a great book on the period - Lords of Finance: 1929, The Great Depression - and the Bankers Who Broke the World by Liaquat Ahamet. There were several factors, but one that the book mentions is that the USA had a disproportionate amount of the gold supply.

To put this into context, and if you'll allow my own interpretation as I don't think that Ahamet spells this out: gold has no intrinsic value. Instead it represents value inherent in other things like labour, food, raw materials. Gold is good for this purpose because there is a finite supply of gold (you can't just manufacture more tokens easily), it is easily identified (hard to fake) and it is portable. It happens that the total world supply of gold grew roughly at the same rate as the economy for many centuries, so gold was quite useful as a representation of that finite amount of value in the economy of real things. That works if gold is distributed roughly as the economy is distributed, and in general this tended to even out: populations with gold would use it to buy from areas supplying goods and services, so the gold tended to migrate to those economic centres.

Following WW I, these conditions broke in at least two ways. Firstly, the economy was growing faster than the gold supply. This would tend to product deflation in a currency based on the gold standard. Deflation would have been catastrophic for any country which owed money (anyone except the USA, I think), since you would need increasing amounts of resources to pay fixed amounts of debt. Secondly, the gold which represented value was not in the same place as the actual economic output. The USA had a larger proportion of the gold than its economy would suggest, at the time when other countries owed money to it, making it difficult for other countries to adhere to the gold standard.

I should note that Ahamet's account has a great deal more detail, and I'm probably taking liberties with it. I do recommend having a look at the book.