Likely, but just depends on two very important factors that will determine if they are gonna be the richest country or not.

1•Depends on the price of Bitcoin as that 8 years time period (2030) because no one knows what would be the price of Bitcoin during that time.

2• Depends on the quality of their Bitcoin holdings, because tomorrow another country may likely adopt Bitcoin as legal tender before that 8 years and buys more Bitcoin than El Salvador, so in this case are they gonna be the richest country due to their Bitcoin holdings?, No. In my general view of this it a probability and only time will tell .