You can think about it altruistically, that no one else can own the KH shares you own. Thus, you prevent others from making the same mistake and free up their money for, for example, American technology stocks.
In recent years, the stock market has admittedly been a somewhat two-sided playing field, but there have still been several winning sectors available. A few highlights that have offered hundreds of percent increases over ~5 years.
-American big tech companies
-European banks
-European defense stocks
-Helsinki Stock Exchange’s large engineering companies
Addition. I have brought up these sectors from time to time in Vartit, but apart from a brief ownership of Wärtsilä, I naturally haven’t touched those winners myself. 
And Wärtsilä should have been kept in the portfolio, at least for now.