I don't think it's the decline in the value of Bitcoin that has failed bitcoin adoption in El Salvador. But it's more for residents who don't consider Bitcoin as an important currency, so there are still many residents in El Salvador who still prefer to use cash, debit, and credit cards.

And according to research I read on a site, it says that more than 60% of respondents throw away government Chivo wallets after using the $30 bonus. Surprisingly, 89% of Salvadorans have never received remittances with the app, only 3% of respondents have received them in Bitcoin. However, 99% of respondents have never paid taxes with Bitcoin.

I think that this is the peak of the failure of bitcoin adoption in El Salvador, although the government of El Salvador can still improve the situation in order to make bitcoin adoption smoother and more equitable for all citizens and also provide education about the importance of bitcoin currency in life.