Many of the people are basically right on the money but let me give an in-depth answer.
The prisoner's dilemma is the best answer. No one wants to sacrifice themselves to help the group is correct. These guys simply aren't used to leading races period. The entire world and US system is based on chasing marks in rabbitted races. Thus no one is used to leading anything of note.
IF they lead, they are likely to be the sacrificial lamb. Thus there is no incentive for even a mid-packer to take it out. If a mid-packer takes it out, he's likely just helping some other mid-packer in his heat make the final.
So you sit in the back, try to save energy and time your kick perfectly and get lucky. Andrew Jesien did this perfectly and is now in the final when he didn't even make the NCAA final
Now Stephen Pifer did take it out and he did qualify automatically. Why is that? Because he has experience and likes leading. He is used to it.
It's like Tevan Everett in the 800. I interviewed him last night after the 800 and he said he was trying to learn in that heat how to run with the pack but he hated it. He said it used up more energy. I nearly fell over as everyone else in the world hates leading anything.
But if you aren't used to it, it can be a disaster. Trust me, I know.
There also is the thought that if you take it out you might make the final but be wearing yourself out for the final.
When I was coaching Jimmy WYner at NCAA regionals this year,
I looked at the heat sheets and thought "It's very likely he gets 4th in his heat if they sit and kick." Only the top 3 automaticaly advanced. I was also 95% sure that if he took it out in 1:59 that he'd get in on time.
Did I tell him to take it out? No I didn't. And for years, I've railed on coaches that let their athletes sit and kick.
Why did I do this? Well I thought he'd win the battle and lose the war. I thought he'd make the final but have nothing left for that. Physically and mentally he hates leading.
Two weeks prior to regionals, I made him lead his heat for like the first 1300 of the 1500 as he needed the regional time thanks to the now infamous DQ at Heps. Everyone in the field used his perfect rabbitting to his advantage and just blew by him with 200 to go. Like Pifer he was able to rally at the end and get in there automatically but it was a big effort for him.
He was spent for the final and ran awfully.
Look at the NCAA finals this year. In heat 1,
http://www.flashresults.com/2009_Meets/outdoor/NCAA/5-1.pdfEmmanuel and McCarthy had a plan to share the lead. THey went through the 1200 in 2:55. McCarthy, the east regional camp, barely had enough in the tank to get the final 300. In the final, what did he do? DFL.
It was also interesting to note that while Emmanuel did well in the final (3rd) the other guys in heat one that all ran fast in the prelim (339), Bolas , abbot, miller all didnt do great in the fijnal as they were like 7-8-9.
Sure they should be stronger but I'm pointing out that you might get in the final and have little left.
Now let's take a look at something the OP wrote:
Your thinking here represents a fundamental misunderstanding of track and field. It's not your fault as the track world is currently set up to believe that a faster time is a superior time but that's not necessarily the case.
The guys who got in on time in heat 4 didn't do anything better than the guys in heat 1. There is no arguing that. They ran a tiny bit faster off a way faster pace. They did none of the work - Pifer did it all.
If there was a "Beyer speed rating" for track and field, they'd deserve way slower ratings tahn the guys in the first heat.