The chance of anyone in this field moving up in the standings by setting a fast pace from the gun is so small that they all knew it would be stupid to take it.
It's true that whoever has to have a fast pace to run his best is the guy who should take it on himself to make that pace happen (if no one else is there to do it). But who exactly would that have been in this race? We can rightly criticize Leer for COMPLAINING about the slow pace but not being willing to make it fast himself. But Leer wouldn't have broken enough guys by leading at sub-3:40 pace and probably wouldn't have broken the guys who did beat him even if he'd run sub-3:35 pace. He only would have squandered his energy and wound up beaten even worse. Maybe Manzano couldn't have handled that pace at this time, but neither could Leer if he was setting it himself. Same story for anybody else in the race. Name the guy who would have placed higher than he did by getting in front and running sub-3:40 pace from the gun. You can't, because they all would have sat on him like a sofa while he used up the most energy of anybody in the race.
If you're going to lead with the intent of dropping as many people as possible, the pace cannot be moderate or what's called "honest." You must take them to their limits with a hammering pace. That's smart only if your fitness is so much better than that of your rivals that the burden of leading is lesser than the risk of taking your chances in a slow race - i.e., it works if you CAN drop enough of them to have a shot at placing high. The thing is, NO ONE in this field was so much fitter or so good of a frontrunner that they stood a good enough chance of beating any more runners than they did had they set a fast pace early. 1:58 at 800 would have set up a 3:38-ish race, but it wouldn't have broken anyone other than maybe a guy or two. The leader would have gotten swallowed up and been beaten by pretty much the same number of guys that did beat him, if not more. 1:55 at 800 would have strung out the field, but it wouldn't have dropped the main players and it would have been suicide. No frontrunning strategy at either an "honest" or "fast" pace was going to work for anyone.
Again, ask yourself who the slowest kickers in the race were and then check to see how many runners they could have dropped by running at close to their PR pace from the gun without overextending themselves to do it. The fastest kickers were also better overall 1,500 runners, so the slower finishers couldn't have dropped them and wouldn't have done diddly squat for themselves by leading. They did, of course, have a good chance to finish higher if SOMEONE ELSE set a fast pace early. See how it works?