To adopt any kind of new currency you need to educate your population very widely and to reach out to those who are most vulnerable. Countries in the EU that are yet to adopt the Euro are dragging their feet for that very reason and are extremely careful about it, and the Euro is a fiat currency that is much more stable than Bitcoin. With Bitcoin has to be even more careful and I don't think El Salvador was.
You are right to a great extent as most people always have drawbacks with new technologies especially when it has to do with finances, am not of the school of thought that bitcoin has failed in El Salvador simply because of poor motivation of the citizens to adopt the currency one we most look at Bitcoin as a global currency and we must learn to treat it like that, bitcoin has no direct connection with El Salvador except for the fact that the government announced their support for the currency, so in the long run, El Salvador citizens are going to adopt Bitcoin when they're realized it a great opportunity.