https://www.macrotrends.net/1333/historical-gold-prices-100-...
Also, please paint the full picture: How many percent of all 1980 investments retain halt their value or more today? My first guess would be: A small minority.
To paint a full picture, how many people who invested in physical gold still have it, and how many had it stolen or lost it, or were scammed buying something other than real gold?
Gold is considered a commodity investment, and shares the high volatility that is common in this class. (https://view.ingwb.com/sector-and-volatility-commodities)
Gold does have unique historic status as a currency or a backer of currency. I'm not in 100% agreement, but this does mean some see gold as a hedge against large-scale financial trouble.
However, that same historic status has made this asset in particular vulnerable to investment scams. (https://www.aarp.org/money/scams-fraud/info-2016/gold-coin-i...) This is one caution about this investment that you don't have to worry about as much compared to if you invest in, say, pork futures.
I would argue the "safest investment" is a diversified portfolio, personally.
Edit. More background on that:
In 2014, after years and years of my parents droning "think about buying a house," I finally decided to teach my parents a lesson, and show them just how bad their investment advice is.
So in the end, I lost around 53 thousand dollars in total from FX, fees, lawyers, drop of property value, and my ability to sleep well at night.
And in 2016, I got kicked out of Canada, as my employer was unable to secure me an LMIA after trying 3 times.
The only thing that prevented me from hitting the bottom was that I was also saving gold since I was 15, when I first bought few crumbs from semi-legal gold prospectors from China.