Interesting. QE program ceased in 2014 and has remained fairly constant since, so it can't be that. Hyperinflation has not occurred so that might play a part.
What is the explanation for a greater rise in gold in the five years prior to GFC?
Trump tariffs is interesting. One of the often posted bullish signals for gold is its safe haven status. I'm fairly sure most people would agree trade wars create uncertainty and therefore convention would see a flight to gold as a safe haven. No, there is a flight to $US. So that debunks the safe haven argument, at least for now.
The most obvious reason, as I see it, for the recent decline in gold is the $US continues to be the safest bet most likely due to a strong domestic economy and rising real rates in the US. The so called goldilocks state of growth with a perfect level of inflation.
The worry is this pattern could be entrenched and gold is set for a protracted period of trading in a narrow band that just keeps it ahead of cost of production - potentially decades. A pure guess on my part but if interested in the market one should have an opinion on direction and a reason why (a reason that should constantly be monitored ready to change).