I read Original Robert Kirby Article published in 1984 where he explain coffee can investing approach first time. The example which he mentioned about success of Coffee Can was $ 5,000 invested becoming $ 800,000 in company called Haloid, which later become Xerox. I do not have any information about other companies, but it does mentioned some companies holding being more than $ 100,000. I am pasting relevant extract from 1984 publication in which we mentioned about value of various companies in portfolio.
So, we do not know date. I assume same being somewhere near 1980s (article was writted in 1984). Price of Xerox in 1980 was around USD 27 per share, going up high of USD 180 in 1998 and then steep downward decline to USD 35 in 2020 as sourced by me from Yahoo Finance.
Since we do not have any information about other holdings in the Kirby Coffee can portfolio, we can not conclude conclusively. But just wondering, the largest holding in portfolio, Xerox has provided provided total shareholder return of 7.5% p.a. (dividend and price appreciation adjusted with split) since 1980 has When one compare same with S&P 500, it appear very mediocare performance in relative sense.(Please refer to light blue line in Xerox price, that is S&P 500 Index).
Hence, Coffee can may work, but there is no substitute to hard monitoring. Fill it, shut it and forget it applies only to Hero Honda Motorcycle and not for portfolio investing my view.
I am enclosing my calculation for Xerox share return since 1980 in US market.