It's funny how everybody believes they can predict what the president's popularity will be over the next 3 years.
Except for the period immediately after 9/11, Bush has never been highly popular. For most of his term, he has been reasonably popular, and popular enough to be re-elected, but not highly popular.
We need to get some historical perspective here. Presidents who have been highly popular, as Nixon was at the start of his second term, have been destroyed. On the other hand, presidents who have had difficulties and appeared to be finished have rebounded strongly -- FDR, Reagan, even Eisenhower had some problems during his second term.
So I think it's a mistake to project 3 years out into the future based on what is happening now. It seems big now, but in 3 years it may well be a blip. Only time will tell.
His disapproval rating has almost always been going up.