Interesting.I do. I also think that the "hitchhiker" whom they asked about in the beginning has been on their radar from the start. As I have said before (and please excuse me for sounding like a broken record), I firmly believe that new evidence has come to light and that has caused the shift in LE's investigative strategy.
IMO, the "hitchhiker" and vehicle were brought to LE's attention in the first few days of the investigation. Up until recently, these items had been secondary. They were open items, but there was no pressing need to get to the bottom of them. However, I believe that the the new evidence that has come into LE's possession now makes LE certain that BG drove that car (or at least escaped via it). I would not be shocked if we come to find out that the newly released sketch is actually of the hitchhiker that LE asked about in the first press conferences.
And thinking of the girls' families on Mother's Day.
Perhaps the car will be found with the owner some miles from Delphi waiting to be found in a river.