Most conspiracy theories are so fraught with obvious issues that cripple the entire idea that it's difficult to decide which of these to address first. Those claiming that expecting everyone in on the fix to both agree and remain silent is ludicrous are on the money.
But what about the way the race unfolded? Assume there was a fix and everyone was contracted the let Meb win. How likely is it that the race would have played out the way it did? Wouldn't it have been a lot more compelling to have a group or six or eight guys stick together through at least 30 or 35 kilometers and have them fall off one by one, allowing Med to take off in the last half-mile or something?
Most upset marathon wins on non-runway courses don't involve the underdog outkicking the favorite(s) in the homestretch. They unfold exactly like the race today did -- someone makes an early break, the field lets him or her go, and the move ultimately proves to be the best winning strategy that day. This doesn't mean that this strategy is usually wise (look at Kim Smith's debut at Boston in 2011), but that's exactly why it looks so crafty with the benefit of a post hoc assessment.
Meb has proven over and over that he is an incredible racer. He simply wins a lot of competitions, big ones, and knows both how to prepare himself to compete and how to get the most out of himself on a given day, faced with a known set of conditions. Not just at Athens but in a slew of races both in the intervening years and before Athens. They man seems more immune to caving under pressure than anyone I've ever seen.
The bottom line, though, is that even if both the race organizers and the athletes had all for some reason agreed to let Meb win, the idea that this could both work and be kept a secret shatters credulity. The OP is trolling but it appears that like any successful troll he's swayed some people to his contrived position.