I believe it is due to the falling demand for gold.
Only tradition has supported demand after the gold standard was finally abandoned in 1971. As time goes by, that tradition will continue to fade and people will have less desire to hold gold as an asset. Its falling value will also cause a reduction in demand by central banks, and that will eventually result in the abandonment of gold as a purely financial asset.
I decided all of this recently, and I plan to sell my gold as I don't see prices ever going up from here.
Plus the opportunity cost of HODLing Gold if you can HODL Bitcoin is very high. Think about HODLing Gold vs. HODLing Bitcoin from 2015 to 2022. I'm very sure you would have lost relative to Bitcoin.
Although, continuing to observe the Gold market could remain useful, because it's one of the leading indicators to know of the Dollar is going stronger or weaker. Gold Up = Dollar Weak, Gold Down = Dollar Strong.