These are rational, sane people. Let's be realistic. It's going to be between 5 or 6 people, right?
So, we have an Olympic Trials, on a multi loop course for viewing, and after the first loop, most are about 3 minutes back from a pack of about 11. By the end of the second loop the lead pack is probably about 7 guys. With about 8 or 9 miles to go, it will be between 4 or 5 guys.
So, why bother?