Their economy has improved significantly, but that is because Nayib Bukele has found a way to improve social security and boost the economy in many different ways, they do not rely entirely on bitcoin investment to improve the national economy. I remember Nayib Bukele once said they only used a small part of the national budget to invest in bitcoin and if it failed, it wouldn't have a big impact on them.
Bitcoin is just a volatile asset, a financial market, it's funny that some people think that if they accept bitcoin then inflation will go away. Or even if bitcoin becomes a currency, how will inflation disappear if people do not work and do not increase their income?
People that say that probably do not have an idea about how the economy works or they are too optimistic about bitcoin and what it can do, adopting bitcoin could bring foreign investment to that country and as such improve its economic situation, but it is not going to be enough, even in a country that is relatively small like El Salvador, so a government looking to improve its economy cannot just focus on bitcoin, and instead it needs to try to focus on the entire economy and solve whatever issues it may be slowing it down.
A country with a developed economy needs to have good domestic and foreign policies, attract a lot of capital and create many jobs for people...Besides, national security also needs to be prioritized as in the case of El Salvador, the country with the highest crime rate in the world even though it is only a small country. Developing a country's economy has never been easy but people seem ignorant and naive to think that simply adopting bitcoin can improve a country's economy.
Let's also not forget that bitcoin is not the only anti-inflation asset in existence, gold is also a pretty good anti-inflation asset. If stopping inflation were just about using an asset with a limited supply, governments would have done it long ago without the help of bitcoin.