I can no more prove my speculation than Dr. Bostrum can prove his, and have no more need to do so than he does. All any of us can do on this topic is speculate. We'll only know for certain what's going to happen when it happens.
If you can't prove it, then debate it! Dr. Bostrom's argument is not mere speculation - he's a trained philosopher, with a comprehensive argument and plenty of his own assumptions laid bare. If there is any thought to your logic beyond "It is what it is, what will be well be", surely you can find something concrete in there you can challenge.