check out https://www.numbeo.com/health-care/
You have to add - besides the cost of housing - the other costs, including food, transportation, private health (if not public), costs of school for your children (if any), and any number of other factors to make a minimally meaningful comparison.
Lower salary in a country where you don't have to pay for healthcare, university tuition and get 28 days paid holiday a year is a lot more than a higher salary in a country where you don't get any of that.
What does the author try to achieve with such biased statistics?
1) get a job in Switzerland (if you want to stay in EU/Euro countries Germany or Denmark)
2) relocate (with the same wage) in Palermo or Tenerife
seriously, I am taking Palermo and Tenerife as examples of places where the climate is so much better than northern/continental Europe and - generally speaking - the cost of life is a fraction.
But you don't need this spreadsheet to intuitively know this, and the data - since it is an average - cannot be really-really accurate (IMHO), maybe it can be useful within a same country.
And the median would me more interesting.