At first glance it would seem that it would be possible if bitcoin adoption really does increase more in El Salvador like people really using it with good understanding of it and not just for the hype or suggestions. But if you really think about it, there are many things that can happen within that span of time specially when we talk about bitcoin which is already as volatile as it is. Which means that El Salvador citizens adopting the use of bitcoin more alone would not be enough to make the country rich. Because even if the people do so, iif the rest of the world doesn't yet or major fud and dumps happen El Salvador would suffer more losses than gains. That is unless the volatility reduces or if the country itself finds a good back up plans for sudden drastic drops that bitcoin does every now and then.