You can get the El Salvadorian citizenship by just live in El Salvador for minimum of 5 years, swear a loyalty oath and doesn't have any criminal activities for a foreigners [1] I think it's not hard, but you need to be patient to wait for 5 years.
[1]
https://en.wikipedia.org/wiki/Salvadoran_nationality_lawLast year there was talk that a permanent residence permit could be obtained with an investment of 3 BTC, and later this was allegedly changed to $100 000 in BTC. A stay in the country of 5 years is really valid for citizenship, but the exception is the citizens of Spain and Latin American countries with a period of 1 year of stay in the country. Of course, there are still some exceptions when it comes to obtaining citizenship.
Permanent residency status in El Salvador can also lead to citizenship through naturalization, on a time-frame of 1-5 years. Those eligible include:
Persons who are nationals of Spain or Latin American countries, who have established a one-year residency;
Foreigners from anywhere who have established a five-year residence in the territory;
Foreigners who are married to Salvadoran spouses and have established a two-year residency; or Persons who have rendered exceptional service to the nation. (Available only by legislative decree).
~snip~
Singapore is also a country that has a huge income for every native and immigrant, allowing bitcoin to grow rapidly there, and it is possible to achieve status as a Bitcoin hub and become bigger like El Salvador.
In that case, Singapore would be the first rich country/city that would accept Bitcoin as legal tender, which would be a departure from what we can currently see - which is that mainly poor countries are interested in Bitcoin in this sense. In this context, it makes no sense to compare Singapore with El Salvador, which are two completely different worlds, especially when it comes to welfare and economy.