Always set predictions 10 years out. By that time you will have sold your books, made your money, and been forgotten. Hell, even 2 years out can work.
Your an author. Am I right?
The other plan is to reissue your gloom and doom forecasts and change the date of the forecasted blowout by two years. There are several books out that have done that for 20 years. And they continue to sell.