Fixating on the case fatality rate without considering incidence is myopic; this is how the mathematics breaks down.
Say we compare two countries, lets call them Sensibleland and Deludedland, both countries have populations of 1,000,000
1/n
2/n
Say that 10% of Sensiblelands population caught 2020Sucks in a year, giving an incidence rate of 10%/year.
Out of Sensiblelands entire population, 100,000 caught the disease. Out of those 100,000, 30,000 die making Cfr= 30%
3/n
Out of the 1,000,000 who catch the disease, 5% die, making the death count 50,000.
4/n
5/n
6/ n