This is the explanation Silver Institute
http://www.silverinstitute.org/site/silver-price/silver-price-history/1979-1980/
"Simplistic retrospectives of the silver market in late 1979 tend to focus on the high-profile purchases of large amounts of silver and silver futures by various wealthy individuals; in reality, there was a tremendously broad-based rush to buy silver by investors worldwide at the time."
So according to SI, that's what your "all stackers" actually did.
Also gold, etc, those years were high inflation years. Not hyper, government was smarter / more powerful than Zimbabweans.
https://en.wikipedia.org/wiki/Silver_Thursday
"The brothers were estimated to hold one third of the entire world supply of silver
(other than that held by governments)." (note: which was big at that time).
...
"The Hunt brothers had invested heavily in futures contracts through several brokers"
So, one could say that the Hunts didn't do something special, they purchased on the cash market, and hedged it along futures, cranking up the price another time, to then try to sell the stock at the higher price. But in that selling plan the Hunts were frontrunned by others, so that the price already dropped 50% before them, in a mere 4 days.
A very important element was that the Hunts borrowed to buy silver. It just took some margin increases and leverage restrictions by the government, to confront them with bills they couldn't pay, and bankrupt them.
If you think about it, nowadays isn't that different from then, also a broad run on precious metals, selling frontrun already passed and futures hedge on decades high (550 Moz, double the common peak).
And, no high inflation.
One difference though: ZIRP. There isn't much out there that has more upwards potential. It's all frontrunned, and too much savings to increase rates again.
Could be named a "stalemate".
And that's why the negative rates talk, the cash transactions limits and cash withdrawal throttling.
The central planners club need savers to waste enough of their savings on the frontrunned markets.
That includes both buy high and sell low.
Be warned.