Making an investment in Bitcoin is one of the ways they could seize the opportunity in it to change their own economy for good, but before that, there must be some instrumentation laid on ground for the fair policy on how to go about it, this will help them devise a means to invest, the strategy to use and the duration the investment will go for, when there is adequate planning on ground made already, things will work out for them, but before then, they have to have a concession on how to start.
Only Bitcoin cannot turn the fortune of a country. The nation has to put in place necessary economic policies that will improve living standards, improve infrastructure, and attract investors. El Salvador has a good plan for its Bitcoin investment, which is why they have been hodling it for a long time. An example of a country that failed to plan before adopting Bitcoin as a legal tender is the Central African Republic. Lack of planning was the reason why the country's Bitcoin experiment failed.