Assuming 1 person knows 100 people, it would take 1 million deaths to seriously warn 100 million. And since it takes 3-4 weeks from infection to death, during which the warning still wouldn't be personally grave, and infections continue to spread. Thus, the population will be infected until herd immunity is sufficiently high (~60% of population if R0 is ~2.5). [1]

If hospitalization rate is 15% & Infection Fatality Rate (IFR) is 1%, then 9%/0.6% of the population will be severely ill/die within 1-2 years, respectively, just from this one disease. One can do further arithmetic for a given country.

The 'solution' above is clearly unacceptable to the vast majority of people.

[1] Herd immunity threshold Vc= 1 - 1/R0, where R0 is basic reproduction number of a disease https://en.wikipedia.org/wiki/Herd_immunity#Mechanics